Megger Insulation Tester, Megohmmeter 1000V Insulation Tester, Ohmmeter 200MΩ~2000MΩ, 250V/1000V Voltage Tester, Auto Ranging, Data Hold, Continuity Buzzer, Backlit, Shoulder Strap Battery Included

At first, I thought this was just acting as a glorified continuity tester -- when I tried to measure insulation values for an alleged "anti-static" mat and an anti-static bag, it indicated a resistance value very briefly, then went back to "1" (which is the indication for open-circuit).Eventually, it occurred to me to try it against a very old analog multimeter with a 1kV range. I verified that it produces 250V, 500V, and 1000V at the respective settings, and that it accurately indicated the 100Mohm internal resistance of the meter.So, it does seem to produce the voltages claimed, and to produce accurate resistance readings (at least for my single 100Mohm test). I have no other calibration standards to use for this, but I'll assume it's working until I find otherwise.I do wish I understood why it occasionally flashes readings for a fraction of a second before going back to open-circuit. Capacitive effects? Not sure, but it makes it hard to be completely confident in the thing's behavior.If I get a better testing opportunity, I'll post a follow-up.(One other note -- for my unit, at least, the batteries were provided in a pack of 4 and another pack of 2. It took me a while to spot the second pack. The unit DOES include the required 6 cells.)