This is an FM Systems VM771 Video Master Video Automatic Level Control (ALC) unit.It is designed to stabilize video levels and correct luminance in baseband video systems.The unit features a video input/output, a power indicator light, and is designed to operate within an input range of 0.5 to 2.0 volts peak-to-peak.It is housed in a blue metal casing with a mounting bracket for installation. Pre-Owned in Excellent Condition What you see in the photos is what you will receive. Does not come with a power adapter.