These S&W hinged handcuffs are made of corrosion-resistant steel and restrict wrists better than standard chain handcuffs. The inner perimeter measures 5 3/4" to 8". They feature a double-hinged design, a double lock engaging pin and 20 locking positions. Includes are two standard keys. They weigh 11 oz. and come with Smith & Wesson's lifetime warranty. Available in ether Nickel or Blued finish. Hinged design to further restrict movement. Has double lock slot configuration for increased security. Smith & Wesson Handcuffs are fabricated from the finest quality carbon or stainless steel. They are manufactured with heat treated internal lockworks, featuring smooth ratchets for swift cuffing and double locks to prevent tampering. All S&W handcuffs meet or exceed demanding U.S. National Institute of Justice tests for workmanship, strength, corrosion and tamper resistance.