Add a bit of color to your hub and save weight in the process with the BOX One Hub Lockring. Extruded and CNC machined from 6061-T6 aluminum, the BOX One Lockring will fit any Shimano compatible cassette body. Notes: 1. To install the lock ring, use Park Tools HCW-5 Bottom Bracket Lockring Wrench. Please note, Park Tools BBT-18 is not the proper tool for this lock ring. 2. The lock ring should be installed with the larger, slotted side facing the cog and the smooth side facing the dropout. Features: Multiple tool design Extruded precision CNC Shimano compatible Lightweight design Specifications: Material: 6061-T6 Aluminum Outside Diameter: 43.6mm Weight: .25 oz