Voltage range: 0~40V; Accuracy: +/-0.1V; With indicator; IN light is for input voltage, OUT light is for output voltage; Press switch for 1~4s can off voltmeter; Press switch for more than 4s, it can check the error of voltage measurement; Adjustable voltage range: 1.25~37V (input voltage must be higher than 1V); Output current: 3A (Max.); Stable working current: 2A; Oscillator frequency: 150KHz