Without doubt the strongest bicycle specific u lock in the kryptonite line up18 mm kryptonium steel shackle will resist bolt cutters and leverage attacksoversize crossbar with additional kryptonium steel sleeve for double securitydouble deadbolt locking mechanism for extensive holding powercentre keyway design defends against leverage attackssliding dustcover to protect keyway when lock is in usethick vinyl coating to protect bike whilst locked upsupplied with three keys one with a high intensit