The Helios dog chest compression leash and harness combination is composed of a durable reflective 600 Denier nylon and mesh outer shell. This unique construction enables both the top and bottom portions of the harness to adjust according to the chest girth area of your pet. Features durable buckles with dual pull handles both at the top and by the chest area. Places pressure at the sternum of the chest area for added comfort ability while walking your pet on all surface areas while placing less pressure at the proper locations by the chest area. The exterior features reflective embedded mesh technology with added outer-rimmed 3M reflective tubing for added safety during those night strolls. Comes with an accented reflective stitched leash with a Titanium swivel hook connector. Features both rubberized embroidered hand stitching on both the leash and harness. Get outdoors with Helios dog! available in multiple sizes and colors. Sizing guide (Inch l*w*h): harness Dimensions: small: back: 2.75 chest: 17.7 - 22.8 neck: 15.7 - 18.8 Medium: back: 3.54 chest: 21.6 - 27.5 neck: 19.7 - 24.4 large: back: 4.72 chest: 24.4 - 33.8 neck: 26.7 - 34.6 leash Dimensions: small: 4 feet, diameter:.27 - less than 18.7 lbs. Medium: 4 feet, diameter 35 - less than 33 lbs. large: 4 feet, diameter 51 - less than 55.1 lbs.