Defender Sentinel Wireless 21291 4CH Security DVR with 1TB Storage Including 4 Wireless 520TVL Cameras with 75ft Night Vision Cast aluminum, vandal-resistant, camera housing optimized for outdoor use.The cameras are wireless in the sense that they communicate with the DVR surveillance system without wires but they still have to be plugged into a power source as a battery would not be able to provide power to a security camera 24/7.