Flumethrin 4.5% Imidacloprid 10.0% Other ingredients 85.5% Seresto flea and tick collar for large dogs works through contact, so fleas and ticks do not have to bite your dog to die. It is convenient, odorless non-greasy collar; No need for messy monthly treatments. Starts to repel and kill fleas within 24 hours of initial application.
