The Shimano SM-HB20 lockring fits on any and all Center Lock style hubs. After installation of the rotor on the hub splines, this lockring secures the Center Lock rotor by threading into the threads resting in the hub. Simply slide on your rotor, then lightly grease the threads on this lockring and thread on the hub.

As you'd expect from a Shimano product, there's quality machining and finishing with a grey anodized finish. By virtue of a larger center hole, this SM-HB20 is compatible with 15mm and 20mm thru axles.