This speaker derives it's power from 7x AA rechargeable batteries that can be charged by two separate sources, either the DC mains plug pack or via it's inbuilt solar panel mounted on top. The speakers are contained in a robust, weatherproof housing making it ideal for outdoor entertainment. The 900Mhz frequency will allow the speaker to be mounted up to 50 Metres away from the transmitter, through walls and floors with crystal clear sound. So versatile, this unit can be used in conjunction with portable MP3 or CD players, DVDs, TVs, VCD, PCs or any other audio device. Unit supplied with transmitter, receiver, power supplies, rechargeable batteries, connect cables and remote control.