The Kruuse Rehab Hock Protector can be used before and after surgery for chronic arthritis i.e. Osteoarthritis, OCD, ligament injuries, arthritis, ED and other assessments.The hock protector is placed with the tip of the hock out through the opening in the protector and then stretched around the leg and under the joint. CARE: Wash by hand & air dry. Sizes Breed ExamplesXXXS Chihuahua, Maltese, Yorkshire Terrier, PapillonXXS Bichon Frisé, English Toy Spaniel, XS Cocker Spaniel, Fox Terrier, SheltieS Whippet, Kelpie, Bulldog, Beagle, DachshundM Labrador, Border Collie, Springer Spaniel, Golden RetreiverL German Shepherd, Boxer, Rhodesian RidgebackXL Bernese Mountain Dog, Great Dane, Irish Wolfhound We recommend you view the detailed sizing chart below (or download the full guide HERE) to choose an appropriate size for your dog. Please actually measure your dog for the appropriate size. The breed recommendations are only a rough guide. The actual measurements from your dog are more accurate. Measurements on the size chart are of the protector lying flat (so the half the circumference).