Starts killing fleas & tricks in as little as 1 hour. Kills fleas, ticks, and chewing lice. Controls flea reinfestation. Waterproof. For use only on cats of all weights over 12 weeks of age. Questions? Comments? 1-888-908-Tick (8425). Or write to: Sergeant's Pet Care Products, Inc., PO Box 540399, Omaha, NE 68154-0399. EPA Reg. No. 2517-148. EPA Est. No. 2517-NE-02.