Contains Insect Growth Regulator (IGR) to kill flea eggs and prevent reinfestation. Each applicator kills and repels fleas, ticks, and mosquitoes for up to 30 days. Features the Pet SpecifixTM Applicator and Accu-Tip Dispenser, which helps prevent misapplication. Each package contains a 4-month supply. Active ingredients: permethrin 45%, s-methoprene 3%. Other ingredients: 52%. Do not use on puppies less than 6 months of age. Consult your veterinarian before using this product on debilitated, aged, medicated, pregnant, nursing dogs. Do not use on cats.