This collar kills and repels both fleas and ticks for 7 months ... PLUS it kills and prevents flea eggs for up to 7 months, thereby stopping the flea life cycle and preventing reinfestation. The Reflect-X Shield™ focuses the pesticide towards your pet and away from you. Additionally, the Reflect-X Shield™ reflects direct light for up to 450 feet for an added dimension of nighttime safety. Water resistant. For use on kittens 12 weeks of age and older.