Sufficient heat and humidity is vital to the survival of land hermit crabs. While pet stores sell analog gauges they are a huge waste of money. Not only are they too expensive but they are poorly made and not remotely accurate.
I have two large tanks so I really love this product. The console supports up to eight remote sensors. I have four, two sensors per tank. The console shows the room temperature and allows me to click through all four sensors without ever going to the tank. They communicate wirelessly so the console can sit on my desk.
All gauges must be calibrated to determine how much adjust you need to make. Digital gauges do not allow you to actually correct the reading but you can make a note on the back of the unit to add/subtract based on your calibration results.
Try not to place the remote sensor directly on the wet substrate, it will skew your reading.
Reading way off all of a sudden? Check your batteries!