Geyserwise Megawatt Saver Geyser Controller. Control equipment for a compatible solar-assisted water-heating system. MWS solar water-heating controller with MPPT operation. Supports a maximum PV input voltage of 350V DC and solar array up to 4000W. Designed for compatible 1500-4000W geyser elements within the specified resistance range. PV panels, geyser and installation are separate requirements.