I tried one of these flap wheels from WA Grinder in a cordless 1/2" drill, at 1600 RPM, on some slightly rusted 1/4" steel plate.It seemed to operate more smoothly than a wire wheel brush. And, being wider and having a smaller diameter than most wire wheels, it was more controllable. My impression was that the flap wheel was a bit slower than a wire wheel but that's possibly due to the width and the fact that the flap wheel was 80 grit and not something more aggressive. This is my first exposure to a flap wheel. So far, I'm thinking they will be more useful on irregular surfaces.