They are made with heat treated internal lockworks, featuring smooth ratchets for swift cuffing and double locks to prevent tampering. Smith & Wesson handcuffs meet or exceed demanding US National Institute of Justice tests for workmanship, strength, corrosion and tamper resistance. From the original Model 100 series handcuffs to the invariable durability of their restraint chains and leg irons - Smith & Wesson is a proven worldwide leader in handcuff and restraint production.