Triathlon. Time Trial. Cyclocross. Some disciplines are made for 1x. And while our X-Range™ 2x set up has integrated much of the simplicity of a 1x system, there are still times when a single ring is best. The SRAM RED® 1 crankset offers the most demanding racers the right mix of features—aerodynamics, durability and simplicity. Features: Single-ring drivetrain simplifies functionality and reduces weight 48 and 50t variants feature direct mount aero chainrings for better aerodynamics Non-aero chainrings can be installed with a single tool, making gearing changes a breeze SRAM X-SYNC™ wide-tooth, narrow-tooth chainring technology provides maximum chain control Laser-etched chainring finish is more durable DUB™ bottom bracket adds durability and simplicity Can be upgraded to a power meter Specifications: Speeds: 12 BB Compatibility: All SRAM Road DUB BBs Chainring Size: 40, 46, 48, 50 Crank arm length: 165mm, 167.5mm, 170mm, 172.5mm, 175mm, 177.5mm Chainline: 45.0mm BB Spindle Interface: DUB Chainring material: Aluminum Guard: No Guard Bolt Circle Diameter (BCD): Direct Mount (DM) Crank arm material: Carbon Color (Crank arm): Natural carbon