Key Features: SRAM X-SYNC™ wide-tooth, narrow-tooth chainring technology provides maximum chain control,Laser-etched chainring finish is more durable,X-Range™ gearing technology gives you more range and a smoother gear progression, so you\'re always in the right gear,Can be installed with a single tool, making gearing changes a breeze,. Specification: Chainring Size: 36, 38, 40, 42, 44, 46,Bolt Circle Diameter (BCD): 107 BCD,Speeds: 12,Compat - Yaw: n/a,Material (Chainring): Aluminum,Color (Chainring): Black, Grey.