The Satechi BT Wireless Bluetooth Speaker is designed for use with smartphones, tablets, and laptops. It is small and compact enough, especially when closed (see image in the bottom left of above picture), to fit easily in your gear bag. It has a rechargeable lithium-ion battery for up to 6 hours of sound. It has been designed with “Satechi’s signature Bass Expansion System which extends the speakers to amplify dynamic audio range without compromising acoustic integrity. The BT Portable Speaker features a vacuum chamber that opens up like an accordion to mimic the acoustic properties of subwoofers resulting in enhanced bass output.” In addition to streaming music, it also works as a speakerphone for Bluetooth-equipped phones. The Satechi BT speaker is available for $44.99 at Satechi or Amazon.