Portable cassette players are compact devices designed to play audio cassettes, which were popular from the 1970s to the 1990s. These players typically run on batteries, allowing users to enjoy music on the go. They often feature a simple interface with buttons for play, stop, rewind, and fast forward. Many portable cassette players also include a built-in speaker and headphone jack for personal listening. While digital music has largely replaced cassettes, some people still appreciate the nostalgic charm of cassettes and portable cassette players, making them a unique collectible item today.