The SmartPlug Combo Kit includes both a 50A 125V/250V inlet connector and a retro-fit connector. This Kit has been designed so it can be used with 3-wires (125V) or 4-wires (250V). The retro-fit connector is designed to be used with your existing cord. You simply cut off the cord plug on your boat cord. The connector has mechanical cord restraint, color coded wire guides, and a water-resistant cord seal.