I would agree with repto. You have to pay good money to get an accurate thermometer and I have. I bought an electronic digital thermometer from Homershams and that is what I use to test everything (fish tanks, reptile enclosures and incubators. It is accurate to within about 0.1 degrees and is the one I believe. Set the thermostat and test the temperature and alter to suit but ignore everything else. Temperatures will vary over an enclosure from one end to the other and top to bottom, and that is good. The reptile will find the temperature it wants.