Martingale Training Collar w/ ChainThis Martingale Training Collar with Chain is ideal for training. Used with a leash or with your hand, the martingale collar tightens when your dog pulls and loosens when they stop, so its only tight when it needs to be. This martingale collar will give you greater control and reduce the risk of your dog slipping out and escaping. Plus, it's completely adjustable. One size fits all! Key Benefits Tightens when your dog pulls for better control and