Frontline Plus provides your cat with the most complete spot-on flea and tick protection available. In addition to killing 98-100% of adult fleas on your cat within 24 hours, Frontline Plus contains ingredients that kills flea eggs. 3 month supply Kills 100% of existing fleas in less than 24 hours. Continues killing fleas for an entire month or more. Remains waterproof for 30 days, even if your pet swims or is bathed. Approved for use on kittens 8 weeks of age or older.: Size: 6 ct.