Seresto® is a unique polymer matrix collar that offers a continuous supply of two active ingredients: imidacloprid and flumethrin for effective 8-month protection against fleas and ticks. That’s one convenient, non-greasy, odorless flea and tick collar instead of 8 monthly treatments. The active ingredients are stored within the collar. They are released in low concentrations and are distributed over your dog’s hair and skin surface for 8 months. As active ingredients wear off over time, Seresto® for dogs continuously replenishes the skin and coat with a new supply of active ingredients. Fleas and ticks are killed through contact with the active ingredients — no biting required. The Performance you expect from a flea & tick topical in an easy-to-use, 8-month collar. For Dogs 7 weeks and older. For Dogs over 18 Lbs. 8 Months of Prevention