The Extech MA620-NIST is a True RMS, autoranging AC clamp meters offer plant maintenance techs, electrical troubleshooters, and DIYers a test instrument that delivers a combination of high performance and exceptional value. In addition to a host of advanced multimeter and current measurement capabilities, it also has a built-in, non-contact (NCV) voltage detector. You can select auto- or manual-ranging modes, measurement functions cover all types of troubleshooting over and above noninvasive current probe measurements: voltage, resistance, capacitance, frequency, duty cycle, diode and continuity tests. Even measure temperature with the supplied Type K bead wire probe. With NIST Calibration.