How are those different than these?
http://www.caswellplating.com/buffs/nbb350.htm
I've tried the above that I picked up locally, in green, yellow and blue, and while better than I expected, the flap sanding wheels with the foam backing (which I can't find anyplace now) seemed to be the best for flat surfaces. My next order I'm going to try some of Caswell's flap wheels out. I'd love to have one of those belt sanders that was open behind that I could maneuver parts around.