The E421B is comprised of 2 parts: a microphone and a battery box. The microphone can be connected directly with any "plug-in power" recording devices. For those devices with plug-in power, the microphone will be powered by the battery box with 4 AA alkaline batteries. A low cut ?lter is provided with the battery box for cutting out unwanted wind or handling noise. A 5-meter extension cable is included for setting the microphone away from the camcorder/recorder and close to the speakers or performers for capturing good sound. A simple rule for successful audio recording is the closer the microphone, the less problem.