Zodiac Spot On II Flea Control for Cats and Kittens provides relief from flea infestations for up to 4 weeks. This topical treatment kills flea eggs laid on your pet to effectively break the flea life cycle. It spreads completely over your pet's body through the natural motion of the animal. Zodiac Spot On II is an effective and economical product designed to be used once a month. Each package contains a 4 month supply.