MASTECH MS2101 4000 Count Mini Digital Clamp Meter AC/DC Voltage Current Resistance Tester Detector Continuity test, can test the circuit to be on or off. It is designed according to IEC10101 and IEC10102032 concerning safety requirements. Use for measure AC/DC current, AC/DC voltage , resistance, capacitance,temperature, frequency,diode and circuit, etc. When measure DCA, the display can automatically reture to zreo. When measure AC voltage, it can measure the voltage's frequency.