SRAM's XX1 X-Sync Chain Ring mates perfectly to SRAM's XX1 crank. It features a wide-narrow-wide tooth profile to securely hold the chain through the roughest terrain, no chainguide necessary. A variety of sizes ranging from the spin-to-win 28T to the hard-man humbling 38T let you dial in your rig for your strengths or terrain. The unique chainring design allows you to slide slide over the crank arm, so crank removal is not required.