An audio cassette is a magnetic tape recording format used for storing sound. It consists of a plastic shell containing two reels of tape, which is coated with a magnetic material. Audio cassettes were popular from the late 1960s through the 1990s, allowing users to record and play back music and voice. To play an audio cassette, a cassette player, such as a Walkman or a stereo, is used. The tape moves past a playback head, converting the magnetic signals back into sound. Although largely replaced by digital formats like MP3 and CDs, audio cassettes still hold nostalgic value for many music enthusiasts.