The Seresto Flea collar contains two active ingredients that make the flea collar work.
The ingredient in the Seresto Flea Collar that repels fleas and ticks is Flumethrin and the other Ingredient is imidacloprid which is the ingredient that kills off adult fleas and other flea larvae which is very important to stop the flea life cycle and prevent the fleas from getting back on the animal.
The Seresto Flea collar is also waterproof and is still effective after being exposed to shampoo, rain and even swimming and the Seresto Flea collar also has a breakaway mechanism so that in the event the dog gets the collar caught on something then it will release so the dog can get away.