Program Tabs 6pk Dog Green/Red 11-20 Lbs Cat 1-6 Lbs Recommended for dogs and puppies 11-20 lbs in weight and for cats and kittens up to 6 lbs in weight Program works by sterilizing the female flea When Fleas lays eggs they will not hatch breaking the cycle of fleas You must treat all of the dogs and cats in the house with Program in order for this treatment to be effective Each pack contains 6 doses a six month supply