This is a half-check collar for small dogs, suitable for training. Color: Gray Size: M ◆ What is a Half-Check Collar? Half of it is a regular collar, and the other half tightens when pulled. ・Doesn't tighten too much: The tightening of the choke part has an upper limit, so unlike a full choke collar (where the entire collar is a chain), there's less worry about tightening too much and injuring the trachea. ・Signals with sound and feel: When the leash is pulled, the sound of the chain tightening and the feeling on the neck teach the dog "don't pull." Thank you.