Smith & Wesson hinged design cuffs to further restrict movement. The model 300 handcuffs have a double lock slot configuration for increased security. Smith & Wesson hinged 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 Smith & Wesson handcuffs meet or exceed demanding U.S. National Institute of Justice tests for workmanship, strength, corrosion and tamper resistance.