I use the dual thermometer probes to measure the cool and hot end of my leopard gecko viv, the thermometer is very accurate and very cheap as well. If you are trying to measure two different viv areas for your reptile I would highly recommend them - they are water resistant too if you wanted to use them in an aquarium. They are well made and great value for the price
Not yet tried this in my vivarium, but upon expection i noticed the battery does not fit properly in the product. The product only works at a certain angle and once you got it at the angle it keeping it there for it to work. Other than that its a good product.