ONGUARD Bulldog Combination U-Lock Cable Combo U-lock's 13mm/0.51" ultra-hardened steel shackle provides maximum cut resistance U-lock's steel ball click-combo gear system offers superior protection from pick and pull attacks U-lock features 4-digit combination so there's no keys to lose or forget Double rubber coating on U-lock crossbar 4'-long, fully coated and braided steel cable provides more locking options in conjunction with U-lock