"This Generac Indoor Transfer Switch allows you to safely power essential appliances during electrical outages without the need for extension cords. Connect your portable generator to the transfer switch to power furnaces, lights, refrigerators or freezers, security systems and more. Includes 12 circuits and is expandable to 16 circuits. U.S.A. Phase Single, Amps 50, Circuits qty. Includes 12, expandable to 16, Application Residential, light commercial, UL Listed Yes, Dimensions W x D x H in. 17 x 17 x 12, Volts 240. Compatible with generators with 50 Amp outlet from 10,000 to 17,500 Watts Connects to existing load center like a subpanel Accommodates Arc-Fault and GFCI breakers to meet current codes Three 15-Amp single-pole breakers, three 20-Amp single-pole breakers, one two-pole 20 Amp breaker, one two-pole 30-Amp breaker and one two-pole 50-Amp breaker Includes all wires, conduit, fittings and wire nuts Requires 100 Amp two-pole main breaker in existing load center not included UL listed"