An excellent value from the Advantage brand, Advantage for Large Cats offers topical flea prevention and treatment to kill fleas fast* and prevent new infestations. These topical flea drops kill adult fleas on cats before they lay new eggs. Apply at the base of your cat's skull. This treatment works hard for 30 days to treat existing flea infestations and prevent further infestations on cats for up to four (4) weeks. What's more, Advantage for cats is fragrance-free and waterproof. This topical flea treatment is available without a prescription. Your cat must be over 9 lbs. and at least 8 weeks of age to use Advantage for Large Cats. Use as directed by label. *Kills fleas on cats within 12 hours of application