Red 1x XPLR E1Single ring drivetrain simplifies functionality and reduces weight Non aero direct mount chainrings from 38T to 46T can be swapped with a single tool SRAM X SYNC wide tooth, narrow tooth chainring technology provides maximum chain control Ultra light hollow carbon fiber crankarms DUB bottom bracket adds durability and simplicity Can be upgraded to a power meter SRAM Model ID: FC RED 1W E1 Attributes BB Inclusion No BCD Direct Mount SRAM 8 Bolt