ZOLEN Dog Anti-pull Collar, Perfect Dog Training Helper Dog spike collar is an effective dog training tools to train your stubborn friend without producing any pain or injury. You no longer have to rush to follow your dog when you keep your dog on a leash. You can easily stop your dog from eating litter on the road while walking. make it easy for you to train,help you teaches your dog obedience and basic commands. The training collar, also called a no pull collar,is composed of small metal rings linked together and each has a set that tighten and your dog's neck (no pain) when it is being pulled by dog. Similar to a chain bracelet, can be adjusted by removing or adding the links. It simply pinches the skin on the neck, simulating the effect of another canine nipping at the neck. All Polished Surface Argon welded and chrome plated for maximum strength and durability, nylon strap and durable D-ring make it a long lifetime to use