Chainrings to fit FSA or Cannondale direct mount cranksets with a 1x drivetrain configuration. Note: FSA direct mount chainrings require FSA's Modular Crank Lock tool for installation TOOTH PROFILE: Megatooth 1X BCD: N/A CRANKSET TYPE: FSA Modular Direct Mount TEETH: 28t - 34t DRIVETRAIN COMPATIBILITY: Shimano 12 Speed HG+ Only Not sure if this is the one you need? Check out the handy FSA Chainring ID Tool here http://www.fsaeasychainrings.com/