Chainring Sram Boost Eagle 12sp X-SYNC2 30T - BlackChainring Sram Boost Eagle 12sp X SYNC2 30T Black Eagle Technology creates the smoothest, quietest, longest lasting and most efficient drivetrains we've ever made. The radical new look and feel of our X SYNC 2 Eagle chainring is a direct result of SRAM drivetrain engineers studying the performance and wear characteristics of thousands of X SYNC chainrings. The longer, positive rake tooth shape has been designed to work perfectly with the new Eagle