SRAM Red Crankset E1 DUBSingle ring drivetrain simplifies functionality and reduces weight Direct mount aero chainrings for better aerodynamics X SYNC wide tooth, narrow tooth chainring technology provides maximum chain control Ultra light hollow carbon fiber crankarms are 29 g lighter than previous generation DUB bottom bracket adds durability and simplicity Can be upgraded to a power meter Available in 160, 165, 167. 5, 170, 172. 5, and 175 mm lengths