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 FlexFrame Bracket for easy mounting to frame tubing 25mm to 80mm wheter round, oval, triangular, or square. Also features 360° rotation providing the ability to better fit and align with a bike frame"s specific geometry.