Bayer Advantage II for Dogs BLUE, OVER 55LBS. 12 Month Supply Flea & Tick Advantage II for Dogs offers quick relief from fleas for your dog. Advantage II for Dogs stops fleas from biting in a few minutes, and in 12 hours it kills 98-100 percent of fleas. Kills fleas within 12 hours Kills fleas (eggs, larvae, and adult) 30 day waterproof formula for active swimmers