The Hartz Ultraguard Collar is a flea and tick collar designed specifically for dogs and puppies of various sizes, ranging from XXS to XXL. With an EPA registration number of 2596-139, this collar is safe and effective for puppies up to 22 lbs. The Ultraguard Pro model offers reliable protection against fleas and ticks, making it a top choice for pet owners looking to safeguard their furry companions from unwanted parasites.