Four 300W line DC power supply, the use of pure copper toroidal transformer, high efficiency, small heat.LED intuitive display voltage, current and output power, with 10mV/1mA high-precision resolution; with short-circuit, over-voltage, over-current, reverse polarity protection, high stability, reliability; a key to control the output on and off switch, convenient and safe. Widely used in product aging maintenance, battery charging, experimental testing, production testing, electrolysis plating and other industries.