The prong collar herm sprenger is gaining a lot of popularity recently because of its increased use by people. Some might use the herms sprenger for strict dog training. But there are a lot of controversies surrounding the herm sprenger collar. When a dog pulls on the leash, a prong collar tightens around the animal's neck. This can cause significant discomfort and even pain to the dog, which is thought to deter pulling behavior by herm sprenger prong collar.