Pro quality wide range cassette with innovative X-Dome design.X-Dome machined-steel design minimizes weight while minimizing flexLargest cog is aluminumUse with SRAM XX1 11-speed chainSRAM 10 and 11 speed cassettes with 11 tooth cogs have the smallest cog located behind the cassette in the packagingRequires use of XD driver (freehub body)Cassette Body Type: SRAM XD 11/12 SpeedCassette Cogs: 10-12-14-16-18-21-24-28-32-36-42Drivetrain Speeds: 11Range: 10-42Weight: 260 g