Magnum Panel Extension Box with 250ADC breaker with 30A dual pole AC input breaker, MPX-30D The MPX Series Extension Boxes allow additional Magnum inverters to be mounted with and connected to the MP Series Systems Panels. The top of the MPX is designed to allow Magnum inverters to fit seamlessly into the top. The MPX Series comes with the AC and DC breakers and wiring to install another Magnum Inverter. An inverter hood (not shown) is also included with each MPX extension to allow the inverter to be mounted vertically. There are three models of the MPX Series, depending on which MP enclosure it will be installed. Each model has a left and right side version depending on which side of the MP enclosure it will be installed – this ensures correct battery cable lengths.