I use a lot of rotary wire brushes.
Long before they wear down seriously, the wires distort.
Today’s invention is a way easily to quickly reverse the drive direction (without having to stand in a different position) and thus counteract the effect of this distortion.
The brush can slide to each end of the drive shaft and lock there, leaving the other end free to be inserted into eg a drill.
(It’s important to do this early/frequently because brushing with a heavily misshapen tool can cause surface damage).
