The SmartPlug 50A 125V/250V connector has been designed to be used with 3 wires (125V) or 4 wires (250V) in a single connector. This retrofit connector offers superior performance and ease of use. It's designed for use with your current cord set. You simply cut off the cord plug on your Boat/RV 50A cord. The connector has mechanical cord restraint, color-coded wire guides, a water-resistant cord seal, and spring-loaded side levers that automatically lock into the slots on the inlet housing.