Marine dual bus bars are used to bring the wiring from multiple electronics together so that you don't need multiple splices in the wiring before going to your battery. Connect all the positive leads to one side of the bus and all the negatives to the other. On one of the ports (usually one of the ends) run the positive and negative to your battery. By rigging this way you can have a clean installation of all of your 12 volt electronics and run off of a single battery. We recommend coating the bus bar in a protective covering such as liquid electrical tape once installed to avoid corrosion issues in the kayak.