The lightest and most refined premium Round direct mount 1X chainring for Cannondale Hollowgram cranks. Fits all old and new models. Particularly suited for F-si frames. 10/ 11 and 12spd Eagle optimized.. Hollowgram direct mount chainrings allow for flawless 1x9/10/11/12 drivetrain setup. Reliable, extremely light, stiff and clean looking on the bike. Chainring's specific offset creates a lot better chainline compared to other offerings on the market. Size (Mass +/-1g): 28T(55g), 30T(56g), 32T(57g), 34T(70g) Color Black, Green Compatibility Cannondale F-Si Hollowgram Si, SiSL, SiSL2 and FSA Modular cranks like SL-K , afterburner, Comet. 10, 11, 12spd(eagle) compatible Material cnc machined 7075 Txxx Aluminum. Long-lasting construction Finish anodized Chainline 47-50mm (5.7mm offset). Chainline depends on the length of the axle you use and spacers configuration. Tooth Shape Can be used with singlespeed, 1x9, 1x10 ,1x11 and 1x12 as it fits all chains. Tooth shape optimized for quiet work.