The kryptonite kryptolok series 2 mini u lock bicycle security for moderate to high crime areas with a standard length shackle the lock features a 13 mm hardened kryptonium steel shackle and patented deadbolt locking mechanism for extensive holding power kryptonite kryptolok series 2 mini u lock features high security disc style cylinder reinforced sleeve over crossbar and cylinder provides enhanced security protection reinforced internal housing increases resistance to twis