The collar is suitable for most kinds of breed. Small breeds like poodles, yorkshire terriers, corgis, shih Tzu, spaniels, pugs, chihuahuas, maltese, russell terriers etc.; medium breeds like french bulldogs, bulldogs, beagles, dachshunds, collies, bull terriers, Australian shepherds, boxers etc.; large breeds like labrador, labrador retrievers, german shepherd, golden retrievers, rottweilers, huskies, great danes etc.