SRAM RED DUB 1x Aero E1Single 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 Attributes BB Inclusion No BCD Direct Mount SRAM 8 Bolt