The American River Ultra Choke Free Dog Harness is a wonderful harness that is SAFE FOR YOUR DOG'S TRACHEA, because it pulls from the chest and not the neck area. The choke-free design also makes the Ultra perfect as a Seat Belt Harness. And it's amazingly Easy to Use -- simply step in, wrap up and go! The harness has a Velcro closure and a high-strength safety release buckle for added protection. Reflective strips offer safe night walking. The harness looks great on, with trim binding that's the same color as the mesh. Made of Soft Mesh Polyester/Machine Wash and Line Dry. Large (Chest 19"-21"); Medium (Chest 16"-19"); Small (Chest 13"-16"); X-Small (Chest 11"-13"). IMPORTANT: If the dog is on the borderline between sizes, always go down to the lower size, NOT up. The harness needs to fit snugly to work correctly.