The Herm Sprenger Stainless Steel Prong collar is one of the most recognizable and popular names in obedience training tools. A safe and effective alternative to choker collars, it puts even pressure around the neck, about every half inch, pinching the skin in a band. This collar does not apply direct pressure to the trachea, so you can train your dog with little or no tugging, jerking, or pulling. The addition of a center plate connector allows the middle link to be configured symmetrically, enabling the prongs to tighten in the same direction. Made of high quality German stainless steel, the size of this collar can be adjusted by adding or removing the links individually. Features: interlocking links, each link equipped with two blunt prongs. Slightly beveled prong tips unlock easily to put the collar on or to take it off, as well as to increase or decrease the collar in size. Made of high quality stainless steel. Additional links sold separately. Sizing instructions: collar should fit snuggly just below the dog's ears, measure the circumference of dog's neck and add 3 inches.