The Zoo Med ReptiTherm Under Tank Heaters, the best heat source for your pets. Under Tank Heaters are better in all ways for reptiles than "Heat Rocks", mainly because this heating device is underneath the enclosure, and heats up a wider area compared to the heat rock, which just heats a small area and CAN burn your pet reptiles.
These can also be used (when taped on the outside) for sugar glider pets. Tape it on the outside, right beside their sleeping pouch and you got the perfect heat source. If you use Heat Rocks for pet sugar gliders, you may end up killing them.
UTH are the best form of heating as well for reptile that require heat during the night time because it is able to provide heat while not disrupting your pet's sleeping pattern. It's also a lot better than heat lamps because it costs less money, both initial purchase and electricity wise. The ZooMed ReptiTherm can also stick to the underside of your cage. Warranty lasts for 1 year.