Review on TM8812 Ultrasonic Thickness Gauge: Accurate Measurement from 1 to 200mm (0.05-8-inch) by Ben Barrington

I bought this to help me decide when parts on my combine and hopefully other farming equipment will wear out. Most places where I can have catastrophic failures are difficult to measure in any other way. So far it's working well enough. I would have liked a little more range on the underside, but it measures in the specified range. I checked it on a sheet metal with a micrometer and it was within 0.010 inch which is close enough for me. I need only say where I have good steel and where I have tinfoil.