AB premium 1X RaceFace Boost 148 direct mount compatible Oval chainrings are designed for CINCH RaceFace system. This version is for BOOST 148 specific bikes and FAT BIKES (when reversed). Fits: RaceFace Cinch system cranks. RF Next SL, RF SIXC, RF Turbine, RF Atlas, AEFFECT CINCH cranks. 9, 10, 11 and 12spd Eagle compatible.