What makes the ultra choke free patented design unique from other dog harnesses? Trachea safe - choke free patented design pulls from the chest only patented conforming shape fit seam technology - causes harness to conform to dogs chest curve. Patented closure slide adjustability - (other copycat harnesses have little or no size adjustment) our 3 inch webbing allows for 3 inches of size adjustment double d-ring adds strength same color trim binding as the mesh safe night walking reflective strips. Zig zag trim binding stitch - prevents missed stitches and creates a super strong bond matching soft cushion grip nylon dog leashes (sold separate). Safety - the ultra is the perfect design for use as a seat belt harness, pulls from the chest, not the neck double safety closure- Velcro and high strength plastic side release buckle, simple step in, wrap up and go design, soft mesh polyester / machine wash and line dry 10 vibrant colors - red, candy pink, black, royal blue, beige, paisley purple, light blue, apple green, green plaid and red plaid. Important sizing note: the following measurements are the dimensions of the actual product, not of the pet they fit. After measuring your pet, make sure all measurements fit within the following dimensions (with a little room to spare in the chest and neck). Xx-small chest: 9"-11" (most important). Pets weighing: 2lbs.-3lbs. X-small chest: 11"-13" (most important). Pets weighing: 4lbs.-6lbs. Small chest: 13"-16" (most important). Pets weighing: 6lbs.-11lbs. Medium chest: 16"-19" (most important). Pets weighing: 11lbs.-16lbs. Large chest: 19"-21" (most important). Pets weighing: 16lbs.-25lbs. X-large chest: 21"-24" (most important). Pets weighing: 25lbs.-40lbs. Xx-large chest: 24"-28" (most important). Pets weighing: 40lbs.-60lbs. Xxx-large chest: 28"-33" (most important). Pets weighing: 60lbs.-90lbs.