The Smith & Wesson Handcuffs are fabricated from the finest quality carbon steel. They are manufactured with heat treated internal lockworks, featuring smooth ratchets for swift cuffing and double locks to prevent tampering. Available standard chain-linked models or hinged models to further restrict movement. All S&W handcuffs meet or exceed demanding U.S. National Institute of Justice tests for workmanship, strength, corrosion and tamper resistance. These handcuffs feature the M&P Lever Lock which allows users to set the double lock by simply lifting a latch on the cuff. No tool required.