Park Tool DW-2 Derailleur Clutch Wrench

3 mm and 5.5 mm wrench openings Fits Shimano® derailleurs including GRX, XT®, SLX®, Deore®, Saint® and Zee® rear Shadow® Plus (+) derailleurs and all previous Shadow® Plus models   Some models of Shimano® rear derailleurs feature a clutch mechanism that can be adjusted to account for wear or rider preference. The Park Tool DW-2 is a small, thin wrench with 3 mm and 5.5 mm openings designed to fit the clutch tension adjuster on many Shimano® rear derailleurs.