The Ultra 410 features a 12mm double-bolting temper hardened steel shackle providing protection against cutting and torsion attacks in a simple design.It includes an easy to mount rattle free bracket and comes in a variety sizes and packages.12mm thick round temper hardened steel shacklePass through double bolting steel shackle provides anti-twist protectionEasy to use mounting bracket fits most framesPatented double layer key design reduces breakageSecurity Rating: 8 of 15