This harness is really impressive. The material is of course natural leather and it feels very sturdy. I ordered a Large at the stores recommendation, as my chest is 39.5", just between a Medium and Large. Although set on the smallest holes, it fits nicely and I have room to grow. The straps do not extend further than they should like some low-quality harnesses. What's best is that the color piping glows perfectly under black light! I was so impressed with the fluorescence! I will say I recommend handling the harness gently, though, as I have noticed some of the color rubbing off in a few places. If it continues I may need to touch up a few areas. Otherwise, great harness!