High-performance German-engineered charge controller with pulse width modulation for quicker charging and more efficient solar power systems and protects batteries from being overcharged by solar array. Adjusts itself automatically to 12V or 24V system voltages. Features temperature compensation and reverse polarity protection Includes LCD display 50 Amp Capacity Works with Item#s 339615, 339617, 339621, 121126, 121125 and 121130