Do you want to install one of the exterior cameras or the 4th camera on the back of your trailer or 50-90 feet from the MDVR?
You can add this retractable 8 ft 4 Pin Cable for MDVR.
Retracts up to 30 ft
4 PIN Heavy Duty cable.
12 Volt CLA Hard Wire Power Cable for MDVR & Digital Wireless Camera Systems
Top Dawg Electronics
MDVR Heavy Duty 720P Cam with BAR/Handle Bar Bracket
MDVR Stainless Steel HD 720P Bracket Camera
MDVR 720P Heavy Duty Side View Camera for MDVR System