I tried one this weekend, and from initial results, this one may be the forumla I've been looking for. The finish is very nice - a deep, dark, black glow, and appears to be very hard. I had taken a slide's top round down to 400 and the flats to 600. The flats were obviously harder to get to take the treatment - took me about 20 revolutions, but now it looks exceptionally nice. Time will tell!