You can use a proportional like helix or herpstat or the new ones by reptile basics vivarium electronics or an on off type like the johnsons or ranco. The main difference is the proportional stats continuously supply power to maintain a set temp, the on/off type do just that click on to reach desired temp and click off when the desired temp is reached. Many people use reptitemp 500 or the hydrofarm with success but I prefer proportional stats. You can buy flexwatt pre wired or wire it yourself. Belly heat is where the flexwatt is placed on the surface the tub sits on vs. back heat where one or more strips ran down the back. Belly heat is easier for me to maintain more stable temps without working my stats hard.