... controller device, against under-voltage, over-voltage, over-flow, over-load, waterless, etc;automatically recovery;control water height;easy installation ... maintenance-free, safe, reliable, energy-saving, efficient;Photovoltaic water pump, Permanent magnet brushless motor, Maximum power point tracking(MPPT) ... 4 inch 48V screw solar powered solar submersible water pump system (4SPS3.6/80-D48/750)