I bought 2 of these gauges. I was so happy that I finally got one. It's like a novelty Tell Fluke this tech field sensor isn't prime time ready and I'm really disappointed in Fluke as the early release field sensor works about 20 percent of the time without a ground probe and not much better with a probe cuts off Ground probe, while in the field measurements are just inaccurate, everywhere you might think it's just a grounding issue, but I can check if I have a ground and it's still not accurate. I even bought a new fluke test block prv 240 fs to prove it and the meter works great with the unit but I take the meter to our panel and try it out and the readings are everywhere, this meter is no better than t5-1000. So if you are reading this think about buying one to save your money box meaning just isn't accurate.