Review on Extech EX411-NIST True RMS Professional MultiMeter with NIST Certification - Premium Accuracy and Reliability by Reza Cook

This multimeter looked promising, especially with the thermocouple input and large display. There's only one problem; it recalculates all values almost twice. I was about to return the 24vdc power supply I just bought because it said 40vdc. Then I got suspicious and checked other things with the meter. The wall outlet showed 190VAC, the AAA battery showed 2.5VDC, and my computer's 12V power line showed 16VDC. The resistance function often displays negative values and the tone does not work in the continuity function even though the tone icon is displayed. Changing the battery several times didn't help. I can't guarantee the ampere values, but to be honest I don't care, the rest of the device has proven itself. My $4 Harbor Freight handheld multimeter was accurate to within 5%, so why can't this bunch? I also confirmed all of the above with a benchtop multimeter. Save your money and literally buy something cheaper than this and don't waste your time.