XCD rear derailleurs are compatible with Shimano mountain shifters and wide range cassettes. CNC-machined rigid construction partnered with enhanced chain stability allow you to power up and down through a variety of terrains. Compatible with wide range cassettes. Strong spring tension for enhanced chain stability. Clutch mechanism can be turned on to maintain chain tension, or off to allow for easier shifting and easier wheel swaps. Full aluminum lightweight construction. Medium cage fits 1x setups with cassettes up to 46T. Compatible with Shimano 11-speed mountain systems.