The Extech MG325 CAT IV Insulation Tester/True RMS Multimeter combines a 200GO/1000V high range Insulation Tester with a full-featured True RMS Multimeter in a single, compact instrument. The CAT IV safety rating ensures the highest level of protection. Product features include 5 Test Voltage ranges from 50V up to 1000V; Polarization Index (PI) and Dielectric Absorption Ratio measurements (DAR); Low Resistance measurement with Zero function; Programmable Timer feature sets the duration of test; Comparison Mode allows user to set the Pass/Fail values for insulation measurements; Lock Power On Function for hands-free operation and user can manually store/recall up to 99 readings. Multimeter functions include AC/DC Voltage, Resistance, Capacitance, and Frequency measurements.