The reason I assumed it was broken, is because before I removed it, it had a basically even heat gradient. A few degrees across, but not that bad. All of my other snakes are hooked up on a rheostat, with frequent temp checks, but this one isn't. I have a heat lamp, but it makes even my 40 gallon breeder go 100+ degrees, I would be roasting him alive if I put it on a 20 gallon tank. I'll look around and see if I have stuff to hook up a rheostat until friday when I can get a thermostat