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.