Muc-Off Preload Collars. Features: Constructed from 7075 aluminium these CNC'ed preload rings add some bling to your bike while also providing precise adjustments to your crank and bottom bracket tension Compatible with: SRAM 30mm, Race Face 30mm, Easton 30mm, and SRAM DUB 28.99mm Includes Stainless Steel hardware Specs: Description:preload collar Model:30mm/SRAM DUB Color:matte black