Hartz Ultraguard Flea & Tick Collars for Dogs and Cats Fresh scented Kills and repels fleas and ticks, plus prevents flea eggs from hatching for 7 months. Can be worn simultaneously with your dog's regular collar Orange collar with reflective strip reflects direct light from up to 300 feet away for an added dimension of night time safety Water-resistant design won't cause loss of effectiveness if your playful pup takes a stroll in the rain Fits dogs with necks that measure up to 22 inches For use on adult dogs and puppies 12 weeks of age and older