Intense study of chain and chainring wear patterns led to the radical tooth profile that lasts longer, runs quieter and further improves chain retention. – Can be used with Eagle 12 speed or SRAM 11 speed chains – Direct mount rings with 3mm offset fit Boost geometry Eagle cranks; direct mount rings with 6mm offset fit traditional geometry Eagle cranks and GXP spindle XX1, X01, X0, X1 and X9 cranks