A portable Bluetooth speaker is a small, wireless speaker that uses Bluetooth technology to connect to other devices, such as smartphones, tablets, and laptops. It allows users to play music, podcasts, and other audio files from their devices through the speaker, making it an easy and convenient way to listen to audio on the go. Portable Bluetooth speakers are designed to be lightweight and compact, making them easy to carry around and use wherever you are. Many models also have additional features, such as built-in microphones for hands-free calling, and the ability to connect to multiple devices at once.