Review on VIVOSUN Aquarium Thermometer Terrarium Temperature Fish & Aquatic Pets by Joseph Morris

I put all four in my mini fridge to test them out. They've been there for over a month. I check them regularly. As a rule, they are within 1-2 degrees of each other. However, they will sometimes differ significantly. The problem with these tests is that I usually forget to test them until I open and close the door again. And since it's a mini-fridge, even opening the door for a second can change the internal temperature by several degrees. I just checked them, the readings are 34.0/35.8/37.6/38.8 4.8 degrees difference. Cups are very cheap. Although technically they work. They are also not reliable. I had to smear them with saliva to hold them for a while and some of them still fall off from time to time.