Square D by Schneider Electric QO1DM10030TRBR 30-Amp Generator Main Breaker Outdoor Manual Transfer Switch with 30-Amp Twist-lock Receptacle Use to connect to a standby power source to as many as 8 circuits Changes from utility power to a standby source with the flip of 2 QO main circuit breakers Includes a 30 Amp 4-Watt L14-30P twist-lock receptacle in the bottom end wall for direct connection from a generator cord supply Single phase, 120/240 VAC, for outdoor use Mechanical interlock helps ensure that only 1 main circuit breaker is in the on position at any time