The Box One Lockring is extruded and CNC-machined from 6061-T6 aluminum and designed to be super lightweight. Replace that old steel lock ring you have now and save some weight while adding style and color to your whip. Available in anodized red, blue, gold, and black to fit Shimano-compatible cassette bodies. Keep in mind, aluminum is softer than steel, so use care when installing one of these lock rings.