Kryptonite Evolution Series 4 Bicycle Disc Bike Lock (Yellow) 14mm hardened MAX-Performance steel shackle resists both cutters and leverage attacks Double deadbolt locking mechanism has extensive holding power High security, disc-style cylinder with reinforced anti-drill, anti-pull protection system Sliding dust cover protects and extends cylinder life 3 stainless steel keys -- one lighted with high intensity bulb & replaceable battery Key Safe Program