Suitable for small to medium sized dogs. (Larger dogs better suited to the step-in harness). Adjustable in 2 places, they are soft and comfortable for exercise and so great for swimming and playing in the snow. The perfect choice for active, outdoor loving dogs. Extra Large Neck Size 15-17 inches Extra Large Chest Size 22.5-31.5 inches Breed guide Boxer, Border Collie, Staffy Antimicrobial for the protection of the product Special Neoflex material which is kind of like a lightweight wetsuit