"The collar is designed to prevent the dog from pulling by replicating the action of an alpha dogs teeth against the neck. The prong collar does not pinch the skin.
Prong collars must never be turned inside out (with the prongs facing away from the dog's skin), as this may cause injury against the body and head. Plastic tips are occasionally placed on the ends of the prongs to protect against tufts forming in the fur or, in the case of low quality manufactured collars with rough chisel cut ends, puncturing the skin. Like the slip collar, the prong collar is placed high on the dog's neck, just behind the ears, at the weakest point."