The Centaur 10-speed cassette has been totally redesigned for 2011. New Ultra-Drive technology uses a synchronized tooth design across the cogset to ensure lightening fast shifting and flawless interaction with the newest Centaur 10-speed chain. Hardened steel cogs with nickle chrome surface treatment for quiet, efficient performance and excellent durability. Eight individual cogs for easy replacement of commonly used gears while the largest two are secured to an alloy frame for added stiffness. Lockring included.