TDK Cassette Tape Deck Demagnetizer.
For those people who still use cassette tape decks. Apparently, over time, the passage of magnetically-charged cassette tape over the metallic parts of the tape deck will impart a magnetic polarity that can impair playback and tapes to record accurately. Cassette demagnetizers (sometimes known as degaussers) were developed to remove this polarity and ensure accurate sound reproduction. Read more