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 on contact with no painful biting required. Inside the unique 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!