The SRAM Force AXS eTap Rear Derailleur in Black is a high-quality aluminum component designed specifically for mountain bikes with 12-speed drivetrains. This rear derailleur from the renowned brand SRAM features a medium cage derailleur cage length, ensuring smooth gear changes and precise performance. Compatible with a variety of bike types, this rear derailleur is a crucial part for any cyclist looking to upgrade their cycling experience with smooth and reliable gear shifting. New open box