Sergeant's Sentry Fiproguard Max Topical Treatment for Dogs 89-132 lbs - 3 Count SENTRY Fiproguard MAX is a topical flea and tick treatment that contains the same veterinarian-recommended active ingredient, fipronil, found in Frontline brand products.* But with Fiproguard MAX, the power of fipronil is maximized with the addition of a second active ingredient. It's is so fast and effective, it prevents reinfestation from fleas, ticks and chewing lice.