With a single 50-amp 125/250-volt power cable, you can draw 30 amps, 250 volts from two 30-amp/125-volt shore power receptacles safely and intelligently. Both legs of the adapter must be plugged into the power source before current will flow.
Will function only if the polarity at the power pedestal (that is; hot and neutral) are not reversed, and inputs are of opposite phase. Since the power is derived from two shore power receptacles, the maximum allowable current (without tripping circuit breakers) is 30 amps at the boat inlet. Lifetime warranty.