SRAM XX1 Eagle Boost Crankset - 175mm 12-Speed 32t Direct Mount DUB Spindle Interface Gray 55mm Chainline. The XX1 Eagle crankset features a special hollow internal architecture combined with SRAMs Carbon Tuned technology to provide extreme stiffness and light weight. An X-SYNC 2 chainring offers significantly quieter performance with better mud clearing and extraordinary durability. As a part of the SRAM Eagle ecosystem this crankset was developed for a superior 1x drivetrain experience.