Premium Sram compatible Oval chainrings are designed specifically for Sram cranks that have 1 hidden chainring bolt behind the crank arm like Sram Red, Red eTap, Red22, Force1, Force22, Rival, Rival1 and more Outer ring includes replacement hidden bolt only, reuse other sram chainring bolts Increases traction and power while decreasing knee stress and fatigue Individually optimized timing based on ring size Works with 2x system with no modification necessary 110mm 5-bolt 52T 7075AL Black 1/9/10/11/12sp Standard