PetLock Plus for Dogs quickly and effectively treats and prevents fleas, flea larvae, chewing lice, mosquitos, mites and ticks! Contains leading ingredients Fipronil and s-methoprene to kill fleas and prevent their eggs from developing! Once treated, monthly applications will keep your pet free of pesky intruders! Includes: 4 month supply
Small is for dogs from 5-10 lbs.
Medium is for dogs from 11-20 lbs.
XL is for dogs from 55+lbs.