Test electrical function by UL & cUL standard, Heavy-duty round power adapter plug for generator 100% cooper conductor inside. Molded with electroplate copper terminal in order to avoid surface oxidation effectively. 1 piece compact style Adaptor for generator L5 120V to L14 120V/250V home transfer switch or house panel. AC Power Adapter L5-30P to L14-30R 125V/3750W. Generator L5 30 AMP 3-prong locking male plug, L14 30 AMP 4-prong locking female connector (X-pole connected to Y-pole ,two hots bridged)