Kryptonite New York Chain 1217 Bicycle Lock with Evolution Series-4 14mm Disc Bike Lock New York Chain with EV Series 4 Disc Lock from Kryptonite 12mm six-sided chain made of triple heat-treated boron manganese steel for ultimate strength Narrower inner width of individual links prevents leverage attacks Weatherproof nylon jacket allows compact coiling and protects bike surface EV series 4-disc lock is 14mm hardened MAX-performance steel shackle with double deadbolt locking mechanism