Carhartt Nylon Duck Training Dog Harness. Fully-adjustable dog harness that provides comfort and control Rugged on-leash training harness is built with two attachment points: one on the back for day-to-day walks, and one on the chest for increased control that helps you work against pulling Built with comfy cushioning, our durable duck fabric, and reflective stitching for safety in low-light situations Custom durable slotted metal D-ring for top lead and front lead. Small and Medium size vests have fixed chest straps, Large and X-Large have adjustable chest straps Sizing: Small (Chest Girth: 17"- 22") Medium (Chest Girth 22"- 28") Large (Chest Girth 27"- 36") Extra Large (Chest Girth 35"- 42") The closer your measurement is to the middle of the size range the better the fit. See sizing chart in images