Without doubt the strongest bicycle specific U-lock in the Kryptonite line up , 18 mm Kryptonium steel shackle will resist bolt cutters and leverage attacks, Oversize crossbar with additional Kryptonium steel sleeve for double security, Double deadbolt locking mechanism for extensive holding power, Centre keyway design defends against leverage attacks, Sliding dustcover to protect keyway when lock is in use , Thick vinyl coating to protect bike whilst locked up , Supplied with three keys, one with a high intensity LED and a replaceable battery, Dimensions: 8.3 cm x 15.3 cm.