Cold forged aluminum X-Sync chainrings for 12 speed Eagle systems Available in Boost compatible 3mm spacing as well as standard 6mm X-Sync� 2 chainring design increases chain retention, wear life, and reduces friction and noise Eagle� Technology creates the smoothest, quietest, longest lasting and most efficient drivetrains Sram ever made The longer, positive-rake tooth shape has been designed to work perfectly with the new Eagle� chain to increase chain retention and overall pedaling efficiency, while decreasing friction, noise and wear 3mm offset is for use with Boost spacing, 6mm is standard Non-Boost spacing Direct Mount 32T Aluminum GXP/BB30 Black 12sp Narrow/Wide 6mm