Give your dog long-lasting protection against fleas and ticks with a Seresto Large Dog Vet-Recommended Flea and Tick Treatment and Prevention Collar for Dogs Over 18 lb. Unlike other flea and tick protection, Seresto Large Dog flea and tick collars kill and repel fleas for eight continuous months. Seresto Large Dog flea and tick collars are recommended by veterinarians, stocked by 8,000 vet clinics and have been trusted by pet owners for nearly a decade. Seresto Large Dog collars make your dog's comfort a priority by killing on contact, so pests don't have to bite your dog to die. Existing fleas die within 24 hours of application while reinfesting fleas are killed within just two hours, before they lay eggs, preventing further flea infestation. Re-infesting ticks die in as few as six hours, and tick infestations are eliminated within 48 hours of the initial application. Seresto Large Dog collars protect against common pests like deer ticks, American dog ticks, brown dog ticks and Lone Star ticks; they're also effective against chewing lice and aid in the treatment and control of Sarcoptic mange. Fleas and ticks not only cause discomfort; they can also transmit bartonellosis, tapeworms or Lyme disease. Check the product label for information on potential side effects. Seresto Large Dog collars are for dogs at least 7 weeks old, and there's no prescription needed. They're odorless, non-greasy and water resistant to swimming, exposure to rain or sunlight, bathing and shampoo treatment. Seresto Large Dog is a trademark of Elanco or its affiliates. Elanco Animal Health, data on file. Seresto Large Dog is water-resistant and remains effective following a shampoo treatment, swimming or after exposure to rain or sunlight. Under normal conditions, effectiveness lasts for 8 months. In order to maintain an eight-month duration, dogs must not be bathed more than once per month. For dogs that swim once a month or more, the control duration is reduced to 5 months for flea control and reduced to 7 months for tick control.