The Blaupunkt Atomik PS30 Wireless Bluetooth 30W Outdoor Party Speaker is a powerhouse in your hand! 30W speaker drivers at a special angle with big passive radiators at the back, produce thumping bass at super volume! Dual Passive Radiators. That means you get twice the fun from this system. These radiators work together to enhance the sound output maximising it to the limit. And adding to the depth of sound and the boom of the bass. 3000mAh battery is the power station behind this party animal. It keeps the music going for hours outdoors or if the electricity goes out. So no interruptions and nothing to spoil your night.