I would highly recommend an Accu-rite from Walmart. There is a $12 one with a probe you can use to measure the UTH heat. This also measures temp/humidity at the unit itself. Walmart also has a smaller $8 one that only shows temp/humidity at the unit. This thread has a pic of my set up with the probe one on the hot side and other one on the cool side. What type of bulb are you using? I would recommend an infared one if that isn't what you have already, they don't disturb the snake with bright light and you can keep the temp up all night with it![]()