(Sergeant's) FiproGuard for Cats contains Fipronil, the same active ingredient used in Frontline Top Spot for cats. FiproGuard once-a-month topical squeeze-on controls fleas, ticks, and chewing lice. Fast-acting and long-lasting, sustained-release formula protects cats for up to 30 days. FiproGuard for Cats can be used on breeding, pregnant and lactating queens. Waterproof.