Advantage for Large Cats offers topical flea prevention and treatment to kill fleas fast and prevent new infestations. The convenient . easy-to-apply . fragrance-free solution works on contact within 12 hours of application to kill adult fleas before they bite or lay new eggs. Simply apply to the back of your cat’s neck . and the treatment works hard for 30 days . treating existing flea infestations and preventing further infestations on cats for up to four (4) weeks. An excellent value from the Advantage brand . Advantage for Large Cats offers relief for your cat at an affordable price. Your cat should be over 9 lbs and at least 8 weeks of age to use Advantage for Large Cats. No prescription needed. Use as directed by label.