MAGNERASER electric bulk-demagnetizing tool

Still in its original box with instructions leaflet, this device is essentially a large electromagnet with a switch and a handle, intended for use in the wholesale demagnetizing (erasing, that is) of information stored on magnetic media -- any odd kind of info/data OR media that is, recording tapes, computer memory disks and components, or anything else of that sort. I'd imagine it dates from the 1980's, that's about the time I sorta remember finding it somewhere. Not sure what the "IBM" written in red marker on the box lid is all about, nor the blacked-out parts of the printed Company name and info...??