I found with the RBI RHP that I was using on my display cage that running the probe underneath some aluminum foil tape down to the substrate and securing it underneath a light layer of substrate let me set the temps exactly where I wanted them to be and keep it there. Granted it probably wouldn't work with a bigger snake since I'm sure they would find a way to work it loose but I never had a problem with that with my little girl. Plus I didn't worry too much because I tried it (without the snake in the cage obviously) just plugged straight into the wall and with the low ambient temps in the room it never heated the tank up over 94 degrees anywhere (and I did check it with a temp gun).