Prong Collars for Dogs, No Pull Dog Collar, Dog Training Collar for Large Medium Small Dogs, Stainless Steel Adjustable with Comfort Rubber Tips (Medium, 3.0mm, 19.6-Inch)Adjustable Size The perimeter of the dog training collar can be adjusted to 23. 8 inches, suitable for small medium large dogs. You can add or remove individual chains on the dog pinch collar to fit your dog's neck as need High Strength Material Aheasoun prong collar is made of high strength chrome plated stainless steel recommended by trainers. Prong collars for dogs have a silver coating for links that can provide a stable usage period for your dogs