Product Description from the Manufacturer

For 6 circuits, 20 amps and generators up to 5000 watts. Expands to up to 16 circuits as family or business needs change. Cabinet can be flush or surface mounted indoors, and allows hardwired or plug-in generator connections. Designed with off-the-shelf circuit breakers for easy replacement or expansion. Includes L14-20 male power inlet and dual wattmeters to help balance generator loads. Includes two 15-amp 1-pole breakers, two 20-amp 1-pole breakers, and one 2-pole 20 amp breaker. You must install a 60 amp main breaker in existing load center. UL 1008 Listed.

Source from Amazon