Extech PQ2071 TRMS AC Power Clamp Meter 1000A is a multifunctional unit that works as an AC Clamp Meter, Multimeter, Power Meter and Voltage Detector. Extech PQ2071 measures the quality of power on 1 and 3 phase systems, can measure all three phases at once once using two sets of leads and the built in clamp, and takes all the standard multimeter electrical measurements.