Keep pesky bugs away from your pooch with K9 Advantix Flea, Tick & Mosquito Prevention for Large Dogs. K9 Advantix works to kill and repel fleas, ticks, mosquitoes, biting flies, and lice. The topical formula is designed to work within 12 hours of initial application to stop existing flea infestations on dogs. It also helps prevent new ones by killing adult fleas on contact before they lay new eggs or bite your dog. K9 Advantix offers fast relief so you and your dog can get back to the things you love most. Your dog should be at least seven weeks old and weigh 21–55 pounds to use K9 Advantix Large Dog. Use as directed by label.