3 month supply. For use only on dogs & puppies 23-44 lbs over 8 weeks of age. Contains fipronil, the active ingredient used in Frontline Top Spot for dogs (Pronyl OTC for dogs is not manufactured by or distributed by Merial. Frontline and Top Spot are registered trademarks of Merial). Kills fleas; kills ticks; kills chewing lice; waterproof. Pronyl OTC for dogs provides three way protection that kills fleas, ticks, and chewing lice. Controls mites that may cause sarcoptic mange. Kills deer ticks that may transmit Lyme disease. Kills brown dog ticks, American dog ticks, and Lone Star ticks. Prevents flea reinfestation for 4 weeks.