A standard audio cassette

An audio cassette is a type of cassette which can store music and sounds. To play a tape, a cassette player or cassette recorder is used. This is also known as a cassette deck, by analogy with reel-to-reel decks. Cassettes store the sound on a magnetic tape that is wound around the two reels in the cassette. Like vinyl records, most cassettes have two sides, called the A-side and B-side. The listener flips the cassette over to play or record on the other side. Some players have auto-reverse, meaning they can play both sides on their own. Cassettes have a tab in the upper left corner that can be removed to prevent accidentally recording over the tape. Cassettes typically hold anywhere from a few minutes up to an hour of audio per side. The longer the tape, the thinner it must be. Tapes longer than 60 minutes (30 minutes per side), and especially those longer than 90 minutes (45 minutes per side), tend to be fragile and more likely to break or get jammed inside the player.