This two camera system is complete with a power harness, two (2) 130° CCD cameras with 50 foot infra-red night vision and all the wires, connectors and mounts you will need. Includes MULTIPLEXER CONTROL BOX / Three Channel Multiplexer with 3 positive triggers and aircraft grade connectors. This multiplexer connects to the fuse box in the vehicle and allows you to connect up to three cameras to your system. Purpose of the Multiplex Module. Connects Multiple Cameras : It allows you to hook up more than one camera (in your case, two) to a single monitor. Without it, you’d need separate monitors for each camera. Manages Video Feeds : It receives the video signals from each camera and sends them to the monitor, either one at a time or in split-screen mode depending on the system. Trigger-Based Switching : Many multiplexers have trigger wires that connect to your RV’s turn signals or reverse gear. When you shift into reverse, the rear camera feed automatically appears. When you signal a turn, the side camera activates. Power Distribution : It often supplies power to the cameras and monitor, simplifying the wiring setup. Custom Viewing Options : Some advanced modules let you choose which camera to view manually or automatically based on driving conditions. So in short, the multiplex module is what makes your multi-camera setup smart, responsive, and user-friendly. System can be upgraded to the Quad View Monitor where multiple cameras can be viewed simultaneously. Note : The quad view monitor options on this system are for 12V vehicles.