The Smith & Wesson Model 100-1P handcuff is the push pin double locking version of their standard model 100. The push pin double lock is located on the edge of the handcuffs, where the single strand swings through. To double lock these handcuffs simply push the pin of your handcuff key into the double locking pin on the cuffs until you hear or feel a click. The model 100-1P is constructed nickel plated carbon steel. The satin nickel plating is not shiny (non reflective) for an easier grip in tactical situations.