Hmm, 4mm (.1574"). Yep, that would take a while to clean any large surface, but I was thinking about nicks and crannies on sheet metal where its darned difficult to properly clean. If it actually worked that would be a neat tool to have. I'm skeptical because the photos provided indicate a very large laser footprint on the items "cleaned". I read all 10 reviews and came away with the impression they were "fabricated" due to the word usage and order. Too good to be true? Yes I think so. Then again, it could be very useful for some very specific cleaning requirements if it actually works.
