Small is made for the small toy breeds and some smallish cats.

Medium is for the small breeds up to say a chubby Corgi or a Sheltie and bigger cats.

Large was made for a standard poodle sized dog.

Extra Large is for Great Pyrenees, a large Bouvier and a Great Dane. *The swivel clip has been tested and will break at 300lbs of pressure, so it won’t hold a small horse.

Fabric version is right between the small and medium sizes.