When it comes to ATB the best way to heat the cage is using a Radient heat pannel. yea you can offer belly heat, but generaly the only time they are on the ground is maybe durring the day ion their hide if its on the ground (my atb has a hide on the ground) if you have a large enough cage offering both is a great thing ^^. a + to raident heat pannels hwoever is that while they do produce a nice amount of heat, they will not burn your reptile if they get to close to them.