IT-803B Digital Insulation Tester with 200 GOhm Maximum Resistance - Perfect for Electrical Safety Testing in Industrial, Commercial, and Home Applications

Plain and simple, it does not work. It displays crazy ever changing readings no matter what setting you are using. Won't read voltage or measure resistance at all.---Update: after changing the off brand batteries this came with, to brand new name brand unit now reads.... Somewhat... Does not read below 0.29 megaohms even at dead short. Unit is only rated to read down to 0.1 megaohms so it is not very ideal for making any precise measurements.The only only upside is it pushes a lot of current compared to other low end megaohmeters, if you learn to identify the poor reading being displayed it will show you a dead short even in corroded conditions.I can use this unit to read continuity through a very rusted tenpenny nail without even making contact with it. Will read through 1/8" air gap on 5KV setting.I know that it's not a proper test, but can be compared to some real world intermittent shorting conditions.I hope this helps potential buyers identify if this unit will benefit them before buying, as I was the test subject.