I don't know. I've been using cheap ($10 - $12 USD) kitchen thermometers for a long time now. I check them against a Paterson Color Thermometer and they all read within a few tenths of a degree F. In my book that's more than close enough and great value for the money. The dial thermometers are all over the place. Some can be adjusted, some not; and I don't bother with them any more.