For SRAM Red, Force, Rival, Apex, S900/950, S500/550, S150, and Quarq-CinQo crank models (not for 2012 'New-Red' cranks with hidden-bolt spider) Ew-Red/Red-Quarq (Yaw) X-GlideR chainrings are only compatible with hidden-bolt Exogram crank arm designs due to the needed clocking of the ramps/pins Outer-position conversion chainrings for non hidden-bolt cranks (NHB) are also available to update older SRAM 10sp road drivetrains 7075-T6 aluminum, hard anodized finish with PowerGlide ramps/pins for optimized shifting performance (newer black rings can be used to replace older tungsten grey rings of same BCD and arm/spider profile).