I use Flexwatt for Narcissa's tank only because it came with the 20 gallon I had for my old bearded dragon. That with a ceramic heater is enough in the winter. My other small one is just a normal one bought from a pet store. I just keep it to give them belly heat to digest. The third one I use is for Kozma which is a human heating pad. That one works the best. Three settings, no hot spots, no light needed.