Seresto Flea & Tick Collar for Dogs—With its innovative delivery system, the Seresto 8 Month Flea & Tick Collar for Large Dogs & Puppies offers a breakthrough in tick and flea control for your precious pup. This veterinarian-recommended treatment is specifically formulated to repel and kill fleas and ticks through contact with no painful biting required. Inside the patented polymer matrix of this easy-to-use, non-greasy, odorless collar are two active ingredients—imidacloprid to control flea infestations, and flumethrin to repel and kill ticks, larvae and nymphs. These ingredients work together to provide dual-action protection against parasitic pests for up to eight months! Safe for use with dogs and puppies ages seven weeks and older weighing over 18 pounds. Do not use with cats.