Review on Test, Measure & Inspect Supplies for Midwest Brewing and Winemaking by Brent Peterson

I verified this by comparing readings in water at various temperatures, from room temperature to boiling, using a digital thermometer for comparison. In the range of a typical beer mash, 140-160 degrees, the accuracy seems to be a degree or two. However, the scale is small enough to be a little hard to read. Do not expect high accuracy from this device. I bought this to be able to measure the temperature in my mash tun lower than my supermarket digital thermometer can reach, so it's useful for that purpose. DO NOT expect to be able to use it for any meaningful or accurate readings below or above the range I mentioned as it turned out to be horribly wrong the farther from 150 degrees it got.