The little gem on the right is a TEAC E-1 tape recorder head demagnetizer. Tape has magnetic particles that adhere to the base tape “ribbon”. As the tape passes over the recording, play and erase heads of the tape machine the heads become magnetized. Of course, the erase head is already magnetized, so that’s another story there.
A tape demagnetizer, such as the E-1, is used to remove the magnetism from the play and record heads. Note that on many machines the play and record heads are one and the same, hence the designation “record/play”.
The TEAC E-1 model that you see here is a true “vintage” piece. It was made in the 1970s but it still works fine. The cool thing about it is that it came with the original instruction sheet in addition to the box.
Now all I have to do is get to work demagnetizing the heads on the various machines.