The SRAM RED eTap rear derailleur wirelessly executes shifts the instant you demand. It's easy to set up, clean in appearance and delightfully uncomplicated. Mechanical necessities such as a carbon pulley cage, ceramic pulley bearings, and anodized alloy artfully blend with proprietary electronic advancements to deliver a shifting wonder.SRAM eTap shift logic and wireless operation2x and 1x compatibleOrbit chain management technology keeps drivetrain quiet and secureLarger X-SYNC pulleys and ceramic bearings for increased durability and efficiencyFits all 11-speed SRAM road cassettes up to 11-32tBattery sold separatelyItem SpecificationsCage LengthShortColorBlackDrivetrain Speeds11Largest Cog32Rear Der/Shifter CompatibilitySRAM eTapRear Derailleur Mount Type10x1 Standard