Material 100% CNC Machine 7075 Aluminum Weight 30T Mtn: 58g 40T Gravel: 106g Tooth Count 30, 32, 38, 40, 42, 44 Offset Mtn: 0mm & 3mm Gravel: 3mm only Chain Compatibility Shimano and SRAM 9-12spd, SRAM 13spd Color Black Chainline w/ eeWings 3mm offset yields 47mm or 52mm chainline (on eeWings AR vs. eeWings Mtn, respectively) 0mm offset yields 55mm chainline