Sram: SRAM X-SYNC 1X chain rings provide the highest level of performance and durability. The SRAM X-SYNC tall square teeth edges engage the chain earlier than traditional triangle shaped teeth. The sharp and narrow tooth profile, as well as rounded chamfer edges, help manage a deflected chain. To provide the best possible performance in muddy conditions, the X-SYNC chain rings have been designed with mud-clearing recesses for the inner chain links and rollers. Engineered in Germany, X-SYNC rings are an integral part of the SRAM 1X drivetrain. Chain rings come with 5x Washers and 1x Bolt: The washers allow you to use your current chain ring bolts with the S-SYNC ring. The single chain ring bolt is for a SRAM chain set with the hidden bolt fitting system (one bolt directly into the back of the crank arm). This bolt is specific to these chain rings and this crank style.