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