Kryptonite Kryptolok Series 2 Mini Bicycle U-Lock with Transit FlexFrame Bracket, 3.25 x 7-Inch 13mm hardened Performance steel shackle resists cutting and leverage attacks High security Bent Foot design for serious protection and great value High security, pick and drill resistant disc-style cylinder 2 keys - "I" style for easier usage Includes Transit Flex Frame Bracket for easy mounting to frame tubing 25mm to 80mm whether round, oval, triangular, or square