SRAM X-Sync Chainring SRAM X-Sync chainrings feature tall teeth with alternating tooth profiles that hold the chain amazingly well and still provide space for mud to clear. Features Full CNC AL rings SPECIFICATIONSRing Position/Type Chain Retaining Single Ring Drivetrain Speeds10 , 11Chainring BCD110 SRAM Asymmetric40T 110mm BCD Black11. 6218. 037. 00042T 110mm Asymmetric BCD11. 6218. 037. 01044T 110mm Asymmetric BCD11. 6218. 037. 020 | Sram | X-Sync Chainring 42T 110Mm Asymmetric Bcd | Aluminum