ONGUARD 8006 Pitbull Mini U-Lock X4P Quattro Bolt Locking Mechanism delivers unequaled strength by locking the crossbar to the shackle on 4 sides, maximizing pull resistance Massive, 14mm ultra-hardened steel shackle is impervious to prying, jacking or cutting User-friendly, Z-Key Cylinder with BumpBlok and rotating dust cover puts pickers, pullers and drillers out of business Round profile and smooth edges eliminate leverage points Double rubber coated crossbars and shackles protect delicate finishes and paint jobs