SRAM, Rival eTap AXS D1, Rear Derailleur, Speed: 12, BlackWireless electronic eTap shift logic for intuitive shifting, easy setup and reliabilityCompatible with both 1x and 2x drivetrains36t cog max derailleur works with 10 28, 10 30, 10 33, and 10 36 cassettesSRAM AXS enabled, allowing easy personalizationChain management keeps the drivetrain quiet and secureX SYNC pulleys for increased durability and efficiencyBattery and charger sold seperately