Kryptonite new york m18 u lock as a leader in action sports security and the creator of the original bicycle u lock in the bicycle security category in 1971 kryptonite offers premium quality security products features 18mm hardened max performance steel shackle resists bolt cutters and leverage attacks oversized patentedhardened steel sleeve over crossbar for double security double deadbolt locking for extensive holding power high security disc style cylinder center keyway defends against le