Blueberry Pet 3/4-Inch Classic Solid No Pull Ultra-Soft Dog Harness Vest, Medium, Apple Green Stripe Size: Medium Width 15-21", Neck 17-23" Size: Medium Width 15-21", Neck 17-23" Since the reflective threads are stitched into the nylon webbing, it is normal to see that the reflective strings are frayed with the stiches where two layers of webbing are connected. The durability of this harness will not be affected. Please note that the reflective threads are stitched into the webbing on one side only. Picture was taken from a size Medium 15-21" (neck) * 17-23" (chest).