Park Tool SPA-2 Spanner Tool
The SPA-2, will fit one-key release retaining rings on Shimano and Campagnolo cranksets & the adjusting cone on most freewheel clusters (not freehubs). Adjusts to a wide range of pin hole widths. Pin diameter is nominally 0.090" (2.3mm).
I use these for my old iDrive. Works pretty well. Not much to say other then it waits to be used and then it works.