Choose Advantage II for Cats 5-9 lbs, 6 Month (Orange) to keep your small cat free from fleas year-round. The imidacloprid and pyriproxyfen in Advantage II Flea Control work together to kill all stages of fleas. This ends infestations, prevents future ones, and helps keep your cat from contracting diseases and parasites transmitted by flea bites. Advantage II for Cats is easy to use. It comes in a pre-packaged applicator, and all you have to do is apply one to your pet’s skin once every 30 days. Because it’s waterproof, it’s protection will remain in place even after swimming, bathing, or exposure to direct sunlight.