Heat pads, these are zoomed. I think they work the best because the highest i've ever gotten mine are abouot 96. Still use a thermostat just incase of power surges, and96 is a little warm, but they won't burn.

http://lllreptile.com/store/catalog/...ble-and-rocks/

And here a a couple thermostats.

http://www.cheappetproducts.net/Rept...BE-P69363.html

http://www.pet-dog-cat-supply-store....-flypage-15190

The last one is a rheostat. They still work, but are cheaper. I don't think they are as reliable as the thermostats, and most people will tell you to use them on a temporary basis. I have also heard from people who use them as permanent with no problems. I guess you just have to find out and see