Kuryakyn Universal Chrome Helmet Lock Make sure no one walks off with your helmet. The unit works on engine guards, frame tubes, or any other 2 1/4 long straight section of 7/8 to 1 1/2 diameter tube. Features: Chrome finish Keys and hardware included Installs with standard tools Sizes: Small: 7/8 - 1 1/4 diameter tubing Large: 1 1/4 - 1 1/2 diameter tubing