SRAM Limited Tour Edition OG-1090 10-Speed Cassette, 11-23T, Red/Black OG 1090 design merges stiffness, durability, and simplicity in a revolutionary package OpenGlide technology allows for the smoother transition between gears when up- and downshifting PowerDome technology: 8 largest cogs are machined from one piece of chromoly steel, then given a nickel finish Stiffer, more durable and provides better power transfer than any other lightweight cassette Fits on Shimano-compatible 9- and 10-speed hubs, except Dura Ace and Shimano compitable 10-speed wheels that have tall cog splines on the freehub body