SRAM 38T 104mm STEEL BLACK 4B T-TYPEDesigned for use with a 104 BCD interface of any 104 BCD spider, this chainring utilizes Sram`s T Type design and is backwards compatible with EAGLE technology (X SYNC II) SRAM drivetrain engineers optimized this ring to combat the high torque, high wear situations e bike riders face The aggressive tooth design provides better chain retention for a smoother, more efficient pedal feel with a focus on long wear life