Red Dingo Martingale Cosmos 20mm Choke Collar, Medium/Large, Dark Blue Allows for maximum control over the dog without risk of choking, or escape by the dog by backing out Adjustable for perfect fit. Soft yet durable webbing. Abrasion resistant ribbon. All seams are sewn (not welded) for maximum strength 12 1/2 -18 1/2-inch in length, 4/5-inch (20MM) in width