Extech 380366 Insulation Tester+DataloggerExtech 380366 Insulation Tester + Datalogger Insulation Tester + Datalogger Autoranging insulation measurements to 4000M With 250 500 1000V Test Voltages and 1mA test current Key Features: Datalogging function stores up to 16,000 readings with single store or a programmable rate of 1 to 65,000 seconds per sample Three test voltages of 250V, 500V, 1000V Measure insulation Resistance to 4000M with 1K resolution and 1mA test current Large dual 4000 count