Seresto Flea and Tick Collar for Large DogsWant up to 8 months of flea and tick protection for your dog? You've got to try Seresto! Seresto is a hard plastic flea and tick collar that kills fleas and ticks! The large dog Seresto is for dogs over 18 pounds. Seresto is an innovative flea and tick collar. Uniquely developed with a matrix design, the collar protects dogs from the harmful effects of fleas and ticks. It kills fleas and ticks, as well as repels them before they bite. Seresto collar