Kikkerland US10 USB Portable Accordion Speaker Accordion-style design creates a large resonance chamber and makes the sound richer than most other small speakers Can be used both ways, folded flat or not Built in amplifier makes the unit much louder Powered by USB power cable (included) or insert 2 AAA batteries (not included) Measures 3.4 x 4.5 x 1.5-inches folded