Advecta Ultra Dog 21 to 55 lbs. 4pk.

Overview Effectively breaks the flea life cycle by killing all life stages of fleas on dogs and puppies 7 weeks of age and older. Kills fleas and lice within 12 hours of drops application and prevents reinfestations for up to 1 month. Remains effective and provides protection even if pet gets wet.   Contains 8.8% imidacloprid, 44% permethrin and 0.44% pyriproxyfen.   Directions: Part hair on the back and apply to skin between the shoulder blades. Effective for 1 month under normal conditions. In cases of severe flea infestation, retreatment may be necessary earlier than 1 month. Do not retreat more often than once every 7 days. Do not use on cats.