* The radical look and feel of X-SYNC 2 Eagle chainrings is a direct result of SRAM drivetrain engineers studying the performance and wear characteristics of thousands of X-SYNC chainrings.* Longer, positive-rake tooth shape has been designed to work perfectly with Eagle chains to increase chain retention and overall pedaling efficiency, while decreasing friction, noise and wear.* 104mm BCD for use with XX1 Eagle Quarq power meter cranks