That's the only sharpening "gadget" I do use, but I had to modify it just a bit to fit Stihl chain. I also removed the depth gauge do-hicky from it (I don't care for it, too slow and always in the way). I don't use it for touch-ups and such, but when I clamp the saw in the bench vise for a full-blown sharpening I will... once you get on to it the darn thing won't add more than a few seconds to the time required for a loop. It flat works to keep the file a the proper depth, or at least a consistent depth... and automatically adjusts that depth as the cutter gets shorter. Simple, effective, inexpensive and super fast, but be warned, it doesn't do anything to keep the file at proper or consistent angles... that part is up to you.
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What he said!