The kryptonite kryptolok series 2 d lock delivers bicycle security for moderate to high crime areas with a standard length shackle this kryptonite bike lock has a 13 mm hardened kryptonium steel shackle and patented deadbolt locking mechanism for extensive holding power kryptonite kryptolok series 2 d lock features 13 mm hardened kryptonium steel shackle patented deadbolt locking mechanism for extensive holdin