A Dremel tool turns fast! Mine isn’t adjustable speed, and the cone shaped brushes flare out too much for close work in tight spaces. The first one I used separated from the shank and went everywhere. I’m glad that I was wearing my glasses!You get a box full of these things for $10, so I can’t complain about the price. The flat ones seem to be a bit better made than the cone shaped ones, and if you have an adjustable speed Dremel tool or you want to mess with a drill for slower speeds, they might work better than my experience with them. I’ve even considered soldering the brush into the shank one one just to see if it works better.