ONGUARD Bulldog Mini U-Lock (Black, 3.55 x 5.52-Inch) U-Locks BullDog level protection in a compact design. New Z-Cylinder is bump-proof and resists picking, pulling or drilling. Security Rating 63 Snap Lock Quick Release multi-position mounting bracket. 5 laser cut keys 1 micro-light and 4 extra grip keys Micro-light key projects a bright white beam.