Taking advantage of 1x drivetrain systems and wider-range rear cassettes, Aero chainrings provide similar overall range to standard 2x drivetrain configurations while helping to optimize each detail in pursuit of speed- Designed to pair seamlessly with the SRAM AXS 107 BCD power meter spider and SRAM 107 BCD cranks with removable spiders- Drop-Stop B is optimized for SRAM Eagle and Flattop chains- Not compatible with SRAM Rival 107 BCD cranksets with integrated (non-removable) spiders. (models ID's FC-RIV-D1 and PM-RIV-D1)- Made in the USA from 7075-T6 aluminum