How to choose the best flea and tick collar for dogs?

Understanding Flea and Tick Collars

What Are Flea and Tick Collars?

How They Work

Flea‑and‑tick collars protect dogs by releasing active chemicals that interfere with the life cycle of parasites. The collar contains a reservoir of insecticide or repellent, usually a synthetic pyrethroid such as imidacloprid, permethrin, or a combination of ingredients. These substances migrate from the inner layer to the outer surface through a controlled diffusion process, creating a low‑concentration plume that surrounds the animal.

The emitted agents act in three ways:

Contact toxicity: parasites that crawl onto the collar or the dog’s skin absorb the chemical, leading to rapid paralysis and death.
Repellency: volatile compounds create an odor or sensation that discourages fleas and ticks from attaching.
Systemic distribution: some formulations are absorbed through the skin, entering the bloodstream and affecting parasites that bite the dog.

The rate of release depends on temperature, collar material, and the concentration of the active ingredient. Manufacturers design the diffusion matrix to maintain effective levels for several months, typically ranging from three to eight months, before potency declines. Selecting a collar therefore requires verification of the active ingredient, its approved duration, and compatibility with the dog’s size and health status.

Types of Active Ingredients

When evaluating a flea‑and‑tick collar, the active ingredient determines both the speed of kill and the spectrum of protection. Understanding the chemistry helps avoid ineffective or unsafe options.

Common synthetic classes include:

Pyrethroids – compounds such as permethrin, flumethrin, and imidacloprid disrupt nerve function in adult insects. They provide rapid knock‑down and are effective against both fleas and ticks. Some formulations combine two pyrethroids to broaden coverage.
Insect Growth Regulators (IGRs) – methoprene and pyriproxyfen interfere with larval development, preventing population buildup. IGRs complement adult‑killing agents but do not eliminate existing infestations.
Organophosphates – dichlorvos acts on the nervous system of parasites. Use is limited because of toxicity concerns; collars containing this class are generally restricted to short‑term, high‑risk scenarios.
Neonicotinoids – imidacloprid belongs to this group and targets flea nervous tissue. It offers sustained efficacy but may be less effective against certain tick species.

Natural alternatives appear in some collars:

Essential oils – citronella, eucalyptus, and cedar oil possess repellent properties. Their efficacy is typically lower than synthetic agents and may vary with environmental conditions.

Selection criteria should focus on:

Target species – ensure the ingredient covers the specific parasites present in the dog's environment.
Safety profile – verify that the compound is approved for the dog’s size, age, and health status; avoid formulations with known neurotoxic risks for small or brachycephalic breeds.
Duration of action – compare labeled protection periods; longer‑lasting ingredients reduce replacement frequency.
Resistance considerations – rotate or combine active ingredients if regional flea or tick resistance patterns are documented.

By matching the active ingredient profile to the dog’s risk factors, owners can choose a collar that delivers reliable, long‑term parasite control without compromising safety.

Why Use a Flea and Tick Collar?

Benefits for Your Dog

A flea and tick collar that matches your dog’s size, coat type, and activity level delivers several direct advantages.

Continuous protection: active ingredients disperse steadily, preventing infestations throughout the day and night without daily application.
Weight‑neutral design: lightweight materials avoid burdening the animal, preserving natural movement and comfort.
Reduced grooming time: fewer parasites mean less brushing and bathing, lowering the risk of skin irritation.
Lower risk of disease transmission: preventing bites limits exposure to Lyme disease, ehrlichiosis, and other vector‑borne illnesses.
Cost efficiency: a single collar can last several months, decreasing the need for multiple topical or oral treatments.
Simplified administration: no oral dosing required, eliminating the chance of missed doses or accidental ingestion.

Selecting a collar that offers these benefits ensures the dog remains healthy, active, and free from parasite‑related complications.

Potential Drawbacks and Considerations

When evaluating a flea‑and‑tick collar, identify any limitations that could affect the dog’s health or the product’s effectiveness.

Chemical sensitivity – Some collars contain pyrethroids or organophosphates that may cause skin irritation, itching, or respiratory reactions in sensitive animals.
Variable efficacy – Protection zones differ among models; a collar may not reach the tail or paws, leaving gaps where parasites can attach.
Duration of action – Active ingredients degrade over time; a collar advertised for eight months may lose potency after four, especially in hot or humid environments.
Interaction with other treatments – Concurrent use of topical or oral preventatives can lead to overdose of the same active compound, increasing toxicity risk.
Size restrictions – Collars are calibrated for specific weight ranges; using an undersized unit on a larger dog reduces chemical distribution, while an oversized one may cause choking or discomfort.
Environmental impact – Ingredients can leach into bedding or soil, posing hazards to other pets or wildlife.

Additional factors merit attention during selection:

Material quality – Durable, waterproof fabric prevents loss of active agents during baths or rain.
Adjustment mechanism – Secure, easy‑to‑tighten clasps ensure consistent contact with the skin without excessive pressure.
Regulatory compliance – Verify approval by relevant veterinary authorities; products lacking certification may not meet safety standards.
User reviews – Empirical feedback highlights real‑world performance, revealing issues not captured in manufacturer specifications.
Cost versus replacement interval – Calculate total expense over the collar’s lifespan; a cheaper unit with a shorter effective period may exceed the price of a premium, longer‑lasting option.

Factors to Consider When Choosing

Dog's Age and Health

Puppies vs. Adult Dogs

When selecting a flea‑and‑tick collar, the dog’s life stage determines the appropriate product characteristics.

Puppies require collars that accommodate rapid growth, lower body weight, and heightened skin sensitivity. The active ingredients are usually formulated at reduced concentrations to prevent irritation, and the collar’s attachment mechanism must allow for easy adjustment as the puppy gains size. Safety standards often mandate a minimum age, typically eight weeks, before a collar can be applied.

Adult dogs can tolerate higher dosage levels because their skin barrier is fully developed. Collars designed for mature animals often provide longer protection periods, ranging from six to eight months, and may include broader spectra of parasites. The fit should be snug yet permit two fingers to slide beneath the band, ensuring consistent contact without restricting movement.

Key considerations for each group:

Size and weight – Measure the neck circumference; choose a collar that covers the full range of the dog’s measurements.
Ingredient potency – Puppies: reduced concentration; Adults: standard concentration.
Duration of efficacy – Puppies: shorter intervals, often 3‑4 months; Adults: up to 8 months.
Adjustment capability – Puppies: collars with multiple size settings; Adults: fixed‑size models are acceptable.
Safety certifications – Verify compliance with veterinary regulatory standards for the specific age group.

By matching these parameters to the dog’s developmental stage, owners can ensure effective parasite control while minimizing health risks.

Existing Health Conditions and Medications

When a dog has chronic illnesses or is receiving medication, the choice of a flea‑and‑tick collar must align with those factors to avoid adverse reactions.

Common health issues that limit collar options include:

Allergic skin disorders – collars that release high‑potency chemicals can exacerbate dermatitis.
Seizure disorders – ingredients such as imidacloprid have been linked to neurologic signs in susceptible animals.
Thyroid disease – certain active compounds interfere with hormone regulation.
Renal or hepatic insufficiency – impaired detoxification raises the risk of systemic toxicity from absorbed agents.

Medication interactions require careful review. Drugs that may conflict with collar actives are:

Steroids (e.g., prednisone) – increase skin permeability, potentially heightening exposure to collar chemicals.
Anticonvulsants (e.g., phenobarbital, potassium bromide) – may potentiate neurotoxic effects of some insecticides.
Chemotherapy agents – compromised immune function can amplify irritation from collar residues.
Heartworm preventatives containing ivermectin – combined exposure to ivermectin‑based collar actives can lead to cumulative toxicity.

The safest approach involves:

Verifying the active ingredient list on the collar label.
Cross‑checking each component against the dog’s current prescriptions and diagnoses.
Consulting a veterinarian before purchase, especially for animals with the conditions listed above.

Selecting a collar that matches the dog’s health profile reduces the likelihood of side effects while maintaining effective parasite control.

Dog's Lifestyle and Environment

Outdoor Exposure Levels

When a dog spends time outdoors, the intensity and frequency of exposure to insects dictate the performance requirements of a flea‑and‑tick collar. Higher exposure increases the likelihood of infestation, demanding longer‑lasting protection, broader spectrum actives, and robust water resistance.

Low exposure: occasional walks in well‑maintained yards, minimal contact with wooded or grassy areas.
Moderate exposure: daily walks in parks, occasional trips to rural trails, intermittent contact with dense vegetation.
High exposure: frequent hiking, hunting, or camping trips; regular swimming; constant presence in tick‑infested habitats.

Low exposure generally permits collars with a 3‑month efficacy window and a single active ingredient such as imidacloprid. Moderate exposure calls for 6‑month protection, often combining imidacloprid with a pyrethroid to address both fleas and ticks. High exposure requires collars offering 8‑month or longer protection, dual‑action formulas, and a waterproof rating of at least IPX5 to maintain efficacy after swimming or heavy rain.

Select a collar whose listed protection duration matches the highest exposure level the dog regularly encounters. Verify that the product specifies resistance to water and sweat, and confirm that the active ingredients cover the prevalent flea and tick species in the region. Aligning these specifications with the dog’s outdoor activity profile ensures continuous protection without unnecessary replacement cycles.

Exposure to Water

When evaluating flea‑and‑tick collars, water exposure directly influences effectiveness and longevity. Collars that lose active ingredients after contact with moisture provide incomplete protection, especially for dogs that swim, bathe frequently, or live in rainy climates.

Choose collars labeled water‑resistant or waterproof; these retain active agents for the advertised duration despite moisture.
Verify the material’s durability; silicone or coated fabrics resist swelling and maintain tension after soaking.
Confirm the release mechanism is designed for wet conditions; some collars use a polymer matrix that releases chemicals consistently when wet.
Check the recommended re‑application interval after bathing; manufacturers often advise a reset period before the collar regains full efficacy.
Review user reports on performance in rainy or aquatic environments; real‑world data reveal whether the collar’s protection holds up under repeated exposure.

Selecting a collar that meets these criteria ensures continuous protection for dogs that encounter water regularly, preventing gaps in parasite control.

Type of Pests Targeted

Fleas Only

When the goal is to control only fleas, select a collar that contains an insecticide specifically targeting flea life stages without acaricide components.

Key criteria:

Active ingredient – Common flea‑only agents include imidacloprid, pyriproxyfen, or (S)-methoprene. Verify that the label lists only these compounds.
Efficacy period – Choose collars offering at least 8 weeks of protection; longer durations reduce re‑application frequency.
Dog size compatibility – Manufacturers provide size categories (small, medium, large). Match the collar to the animal’s weight to ensure proper dosage.
Safety profile – Review veterinary safety data; avoid products with known toxicity to cats if the household includes them.
Water resistance – Opt for collars rated for water exposure if the dog swims or is frequently bathed; this preserves active ingredient potency.
Resistance management – Rotate flea‑only collars with other flea control methods (e.g., topical treatments) to prevent parasite resistance.

Additional considerations:

Inspect the collar for a secure, adjustable clasp that prevents slipping while allowing growth.
Confirm that the product has undergone regulatory approval (e.g., EPA registration) and carries a clear expiration date.

By focusing on these parameters, owners can identify a flea‑only collar that delivers reliable, targeted protection without unnecessary tick coverage.

Ticks Only

When focusing solely on tick control, a collar must contain an ingredient proven to target hard‑ and soft‑bodied ticks. Common actives include permethrin, imidacloprid, and flumethrin; each disrupts the nervous system of the parasite, causing rapid immobilization. Verify that the product’s label specifies “ticks only” or “tick protection” to avoid unintended flea coverage, which can dilute the concentration of the tick‑specific compound.

Key factors for selecting an effective tick‑only collar:

Active ingredient potency: Choose a collar with a high‑dose formulation (e.g., 10 % permethrin) that maintains lethal levels on the dog’s skin for the advertised period.
Duration of protection: Look for a guaranteed efficacy window of at least three months; longer periods reduce the need for frequent replacement.
Size and fit: Measure the dog’s neck circumference accurately; a collar that is too loose allows gaps where ticks can attach, while one that is too tight may cause irritation.
Water resistance: Ensure the collar retains its efficacy after swimming or heavy rain; water‑proof designs prevent active ingredient loss.
Safety profile: Confirm the product is approved for the dog’s weight class and age, and that it does not contain ingredients harmful to cats, especially if they share the household.

Evaluate the collar’s performance data. Manufacturers typically provide laboratory and field trial results showing percentage reduction of tick infestations. Prioritize products with ≥ 90 % efficacy in real‑world studies.

Consider resistance management. Rotating between collars with different actives, or combining a tick‑only collar with a separate flea treatment, helps prevent tick populations from developing tolerance.

Finally, read user reviews for signs of skin irritation or odor issues, as these can indicate formulation problems that affect compliance. Selecting a collar that meets the above criteria maximizes tick protection while minimizing unnecessary exposure to other chemicals.

Both Fleas and Ticks

Fleas and ticks are external parasites that feed on canine blood, transmit diseases, and cause skin irritation. Fleas complete their life cycle in weeks, thriving in warm, humid environments, while ticks attach for several days, often delivering pathogens such as Lyme disease or Ehrlichiosis. Both pests can lead to anemia, allergic reactions, and secondary infections if left uncontrolled.

Collars designed for dual protection release active chemicals that spread across the skin and coat. Common agents include imidacloprid, flumethrin, or a combination of pyriproxyfen and amitraz, which disrupt nervous function in insects and arachnids. The diffusion system maintains a steady concentration, providing continuous coverage without daily dosing.

When comparing options, evaluate the following factors:

Spectrum of activity: verified efficacy against both fleas and multiple tick species.
Onset of protection: time required for the collar to become effective after application.
Duration of efficacy: lifespan of the active ingredients, typically ranging from 3 to 8 months.
Safety profile: low toxicity for dogs of various ages, minimal risk of skin irritation, and compatibility with other medications.
Size compatibility: appropriate fit for the dog’s neck circumference to ensure consistent delivery.
Resistance management: inclusion of ingredients that reduce the likelihood of parasite resistance.

Select a collar that matches the dog’s weight class, offers a proven duration of action, and lists both flea and tick control in independent efficacy studies. Verify that the product complies with veterinary regulatory standards and read the label for any contraindications before purchase.

Collar Duration and Effectiveness

Short-Term Options

Short‑term flea and tick collars provide protection for a defined period, typically one month, and are useful when a dog needs immediate coverage during travel, seasonal infestations, or while awaiting a longer‑term regimen.

When evaluating these collars, focus on the following attributes:

Protection duration stated on the label (usually 30 days).
Active ingredients with documented efficacy against both fleas and ticks (e.g., imidacloprid, flumethrin).
Safety limits for age, weight, and breed; many short‑term models are approved for puppies over eight weeks and dogs above a minimum weight.
Water resistance, ensuring continuous action despite bathing or rain.
Ease of removal and replacement, important for rotating products on a monthly schedule.
Cost expressed as monthly expense, allowing comparison with alternative treatments.

Efficacy can be confirmed by checking for veterinary endorsement or registration with regulatory agencies; a 30‑day guarantee often indicates reliable performance. Verify that the active ingredients are listed in peer‑reviewed studies or official product data sheets.

Selection steps:

Choose a collar that matches the dog’s weight range and age requirements.
Ensure the expiration date exceeds the intended usage period.
Fit the collar snugly but not tightly, allowing two fingers to slide underneath.
Observe the animal for signs of irritation or behavioral changes during the first 48 hours.

Replace the collar at the end of the advertised protection window to maintain continuous coverage. Monitoring the dog’s skin condition and consulting a veterinarian if adverse reactions appear will keep the short‑term solution both safe and effective.

Long-Lasting Solutions

When evaluating collars that promise extended protection, focus on the duration each product guarantees under typical use conditions. Manufacturers usually state a period ranging from three to eight months; choose the longest interval that matches the dog’s activity level and environmental exposure.

Key factors for long-lasting performance:

Active ingredient stability – compounds such as imidacloprid, flumethrin, or selamectin retain efficacy over months when formulated with controlled‑release technology.
Water resistance – collars that maintain potency after swimming or heavy rain prevent premature depletion of the active agent.
Dosage consistency – a uniform release rate ensures steady protection without spikes that could cause irritation or rapid wear.
Material durability – silicone or reinforced fabric resists tearing and maintains fit, preserving the collar’s functional integrity.

Select products that provide independent laboratory verification of their claimed lifespan. Documentation of field trials, expiration dates, and clear usage instructions further confirms reliability. By prioritizing these measurable attributes, owners secure sustained flea and tick control without frequent replacements.

Making the Right Choice

Reading Product Labels

Active Ingredients List

When evaluating a flea and tick collar, the active ingredient list determines efficacy, safety, and duration of protection.

Common active ingredients include:

Imidacloprid – systemic insecticide, kills fleas and ticks after contact with the animal’s skin; protection typically lasts 6–8 months.
Fluorinated pyrethroids (e.g., deltamethrin, permethrin) – neurotoxic agents that repel and kill a broad range of ectoparasites; effective for up to 7 months.
Pyriproxyfen – insect growth regulator that prevents flea development; often combined with adulticides for comprehensive control.
S-Methoprene – another growth regulator, targeting immature stages of fleas.
Cymbinate – synthetic pyrethroid with rapid knock‑down action; provides both repellency and kill.
Spinosad – derived from bacterial fermentation, kills adult fleas quickly; less common in collars but appears in some formulations.

Key considerations for the ingredient list:

Spectrum of activity – single‑ingredient collars may target only fleas or only ticks; dual‑ingredient products address both.
Concentration – higher percentages generally extend protection but may increase risk of skin irritation in sensitive dogs.
Resistance profile – repeated use of the same class (e.g., pyrethroids) can lead to resistant flea populations; rotating ingredients or selecting multi‑mode products mitigates this risk.
Safety for specific breeds – certain pyrethroids are toxic to cats and can be hazardous to dogs with MDR1 gene mutations; avoid collars containing permethrin for such animals.
Regulatory status – ingredients approved by agencies such as the EPA or EMA guarantee tested efficacy and safety standards.

Examples of commercially available collars and their active ingredients:

Seresto® – imidacloprid + flumethrin; 8‑month protection, broad spectrum.
K9 Advantix® – imidacloprid + permethrin; 5‑month protection, strong repellency.
Bayer Protecta® – imidacloprid + pyriproxyfen; 6‑month protection, combined adulticide and growth regulator.
Vetoquinol Flea & Tick Collar – deltamethrin; 7‑month protection, high repellency.

Selecting a collar requires matching the active ingredient profile to the dog’s health status, local parasite pressure, and desired duration of coverage.

Warnings and Precautions

When selecting a flea‑ and tick‑preventive collar for a dog, safety considerations are as critical as efficacy. Improper use can lead to skin irritation, toxicity, or reduced protection.

Verify the collar’s active ingredients match the dog’s size, weight, and health status; some chemicals are unsuitable for puppies, pregnant females, or animals with known sensitivities.
Examine the expiration date; expired products may lose potency or become harmful.
Follow the manufacturer’s instructions for placement: position the collar snugly but not tightly, allowing two fingers to slide between the collar and the skin. A too‑tight fit can cause chafing, while a loose collar may slip off.
Monitor the dog for adverse reactions such as excessive scratching, redness, swelling, vomiting, or lethargy; discontinue use and consult a veterinarian if symptoms appear.
Keep the collar away from children and other pets; accidental ingestion can be dangerous.
Store the collar in a cool, dry place, out of direct sunlight, to preserve chemical stability.
Do not combine the collar with other topical treatments containing similar insecticides unless a veterinary professional explicitly approves the regimen; overlapping chemicals increase the risk of overdose.

Regular veterinary check‑ups should include evaluation of the collar’s condition and the dog’s overall health to ensure continued protection without compromising safety.

Consulting Your Veterinarian

Personalized Recommendations

When choosing a flea‑and‑tick collar, the most effective strategy is to match the product to the individual dog’s characteristics. Consider the following factors before making a purchase:

Size and weight – Collars are calibrated for specific weight ranges; a collar that is too large may release excess chemicals, while one that is too small may lose efficacy.
Breed-specific sensitivities – Some breeds, such as those with thin coats or prone to skin irritation, respond better to collars with lower concentration of active ingredients.
Activity level and environment – Dogs that spend most of their time outdoors in high‑risk areas benefit from collars offering longer protection periods, whereas indoor pets may require shorter‑duration options.
Health status – Animals with existing dermatological conditions or on concurrent medication should receive collars that avoid potential drug interactions.
Age – Puppies under eight weeks and senior dogs often need formulations with gentler release mechanisms.

After evaluating these criteria, select a collar that aligns with the dog’s profile. For example, a medium‑weight terrier that frequents wooded trails would be best served by a collar designed for active outdoor dogs, offering up to eight months of protection and formulated for sensitive skin. Conversely, a small, indoor‑only breed with a history of allergic reactions should receive a low‑dose collar limited to three months of coverage.

Personalized recommendations also involve checking the manufacturer’s label for active ingredients such as imidacloprid, flumethrin, or permethrin, and confirming that the chosen compound is approved for the dog’s breed and health condition. Verify expiration dates and storage guidelines to maintain potency throughout the intended usage period.

Implementing this tailored approach reduces the likelihood of adverse reactions, maximizes protection against ectoparasites, and ensures the collar functions as intended for each individual dog.

Addressing Concerns

When evaluating a flea‑and‑tick collar, owners typically focus on several practical concerns that influence the final decision.

Safety for the animal – Verify that the product is approved by veterinary authorities and that the active ingredients are within safe concentration limits for the dog’s weight class. Look for collars with a non‑irritating, break‑away feature that releases under excessive pressure.
Effectiveness against parasites – Choose a collar that provides proven protection against both fleas and ticks for a minimum of 8 weeks. Review independent studies or manufacturer data that specify kill rates and the spectrum of species covered.
Duration of protection – Confirm the advertised lifespan matches the intended usage period. Some collars maintain efficacy for up to 6 months, reducing the need for frequent replacement.
Potential allergic reactions – Assess the ingredient list for substances known to cause skin irritation or respiratory sensitivity. If the dog has a history of allergies, opt for a hypoallergenic formulation or a collar that uses natural repellents such as essential oils with documented safety profiles.
Fit for the dog’s size and coat type – Ensure the collar’s length and width are appropriate for the animal’s neck circumference. Adjustability is essential to maintain contact with the skin without being overly tight.
Environmental impact – Prefer collars that minimize leaching of chemicals into the environment after disposal. Products with biodegradable components or reduced toxic load meet this criterion.
Cost‑effectiveness – Compare the price per week of protection across different brands. A higher upfront cost may be justified if the collar offers longer coverage and superior efficacy.
Veterinary recommendation – Consult a professional to verify compatibility with any concurrent medications or health conditions. Veterinarians can also advise on the most suitable brand based on regional parasite prevalence.

Addressing these concerns directly helps owners select a collar that safeguards the dog’s health, delivers reliable parasite control, and aligns with practical considerations such as budget and environmental responsibility.

Proper Application and Monitoring

Correct Fit and Sizing

A collar that is too loose allows the insect‑repellent chemicals to escape, reducing protection; a collar that is too tight can irritate skin and impair circulation. Accurate sizing guarantees continuous efficacy and comfort.

Measure the circumference of the dog’s neck at the point where the collar will sit.
Add 1–2 cm (½ inch) to the measurement; this extra space accommodates movement.
Compare the resulting figure with the manufacturer’s size chart, selecting the range that includes the adjusted measurement.

When the collar is placed, ensure the band sits snugly but does not compress the fur. The collar should be able to slide a single finger beneath it. If the collar slides off easily or leaves deep indentations, adjust or choose a different size.

Signs of an ill‑fitted collar:

Visible gaps where the collar does not touch the neck.
Redness, hair loss, or scabbing at the contact points.
Excessive movement of the collar during normal activity.

Regularly re‑measure as the dog grows or loses weight, and replace the collar if the fit changes. Consistently applying these steps secures the proper fit, maximizing protection against fleas and ticks.

Observing for Adverse Reactions

When fitting a flea‑and‑tick collar, immediate observation is essential. Look for skin changes, behavioral shifts, or systemic signs within the first 24‑48 hours. Early detection prevents escalation and informs future product choices.

Typical adverse indicators include:

Redness, swelling, or rash at the neck area
Excessive scratching, licking, or chewing of the collar region
Hives or welts elsewhere on the body
Vomiting, diarrhea, or loss of appetite
Lethargy, tremors, or difficulty breathing

If any of these symptoms appear, remove the collar promptly. Rinse the area with cool water and pat dry. Record the reaction, noting the brand, collar model, and time of onset. Contact a veterinarian without delay; professional guidance may involve antihistamines, topical treatments, or alternative parasite control methods.

Long‑term monitoring remains valuable. Conduct brief checks each day for the first week, then weekly for a month. Consistent documentation creates a reliable reference for selecting future collars, ensuring the chosen product aligns with the dog’s sensitivities and health status.