British Made Electric Erasing Machine, C.1937

After a lifetime of dabbling in antiques, nothing excites me more than coming across bizarre inventions like this one. It states on the box, this is an electric erasing machine. I plugged it in and tried it out, discovering it is in perfect working order. The rotating eraser actually builds up speed, the longer it is left running, which I would imagine can do serious damage if let loose on a valuable drawing or cartoon. This electric eraser was patented by B. J. Hall and Co in 1937. The company was based in Victoria Street, London. Considering WW2 commenced in 1939, I think it safe to assume this dates to some time prior to this. It does not look like the kind of thing that was produced in the UK after the war. It is of all metal construction. The box measures  21cm x  16cm x 8cm. This a hefty contraption, so please add R55 for postage.