For use with Master Lock's universal pin keying system. Laminated case 4-pin tumbler security. Dual steel levers lock both sides of case-hardened shackle. 4-pin tumbler cylinders helps prevent picking. The system utilizes a mounted fixture or punch tool to shear the serrated pins to fit a customers existing padlock key. Padlocks do not include keys. The universal pin system will only work with Master Lock's original key blank or the M1 blank. Universal punch tool is required to match the universal padlock to consumer's key.