I think it was originally designed to get scratches out of jet fighter cockpit windows.

I've used it on wood, and it brings out grain lines you wouldn't normally see. It works so well because the grains shear, rather than scrape or cut. I sanded paduak down to 600 grit then hit the whole grit range of micro mesh. You'd think it had been lacquered when i'd finished. It is truely amazing stuff. And you can wash it. And it's very flexible, being cloth backed, so good for getting into those little blade strengthening areas!! Just make sure you do the leg work in the earlier grits, because it's harder to remove fine scratches caused by earlier grits with the mircro mesh. Also is worth wiping the blade between grits, incase any have parted company from the backing, and get dragged across with the next grit!