It is a 2in1 Digital Tester/Dual Display Voltmeter Ammeter, Operating voltage:DC 4.5 ~ 30V, Measure voltage: DC 0 ~ 100V, Measure current :DC 50A (require external shunt), Measure accuracy: 1% (± 1 digit), It has small size, high efficiency, long term stable and reliable quality,easy installation and use . Applications:Suitable for Charger,Auto, Electric Bicycle,inverter, solar energy, LED lights or other products voltage current measurement.