Engingeered to interface with Bosch motor systems, SRAM drivetrain engineers optimized this ring to combat the high-torque, high-wear situations e-bike riders face. The aggressive T-Type tooth design provides better chain retention for a smoother, more efficient pedal feel focusing on long wear life. Model: CR-TTYP-BO-A1 Steel (36T,38T). AeroGuard Compatible that fufills EN 15194:2017 standard Backwards compatible with other Eagle Technology.