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. Medium Neck Size 12-13 inches Medium Chest Size 16-22 inches Breed guide Spoodie, Maltese, King Charles Antimicrobial for the protection of the product Special Neoflex material which is kind of like a lightweight wetsuit