This is a TDK AH-301 head eraser (demagnetizer) for tape decks. It's quite old. I'm selling it because I no longer need it after getting rid of my tape deck. There are some scratches and dirt, but when I put in batteries (LR44 x 2) and turn it on, the red LED lights up first, and then the green LED lights up after a while, so it seems to be working. However, I don't have a tape deck, so I haven't been able to confirm whether it actually demagnetizes. I plan to send it via Takkyubin Compact. Thank you for looking.