The Shimano RD-M592 Rear Derailleur is a low profile shifter to remove interference issues with rocks and debris along your route. This trail performer makes it easy to shift between gears even on rough terrain. Avoid chain drop as much as possible so that you can ride without issue. Features of the Shimano RD-M592 Rear Derailleur Low profile Shadow design Features direct cable routing and a stronger guide spring 32t minimum low gear for proper function Compatible with all Shimano 9-speed HG cassettes, 9-speed mountain shifters and 9-speed chains