Provides relief from flea infestations for at least 21 days by killing fleas and their eggs laid on your dog or puppy, thereby effectively breaking the flea life cycle. This product also kills Blacklegged Ticks (Deer Ticks) which may carry the organism that carries Lyme Disease. This product contains a powerful, effective insecticide which kills adult fleas and ticks on contact, and Precor, a long lasting insect growth regulator (IGR), which prevents flea eggs and larvae from maturing into adults. Adult fleas spend virtually all of their time on the pet and produce vast numbers of eggs which drop off the pet and develop in the environment. Once fleas are apparent on your pet there is already an infestation of their pre-adult stages in your home. 4 month supply.