SRAM Red DUB 1x Aero E1 Crankset Speed: 12 Spindle: 28.99mm BCD: Direct Mount SRAM 8 Bolt 50 DUB 172.5mm Black RoadSingle 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 SRAM Model ID: FC RED 1 E1 Specifications: BCD Direct Mount SRAM 8 Bolt Crank Arm