Repti Therm U.T.H. Under Tank Heaters are an ideal 24 hour primary or secondary heat source for tropical or temperate reptilian species. All of Zoo Med s Under Tank Heaters are UL/cUL approved and contain a solid state nichrome heating element. These under tank heaters permanently adhere to your terrarium forming a solid bond for optimum heat transfer. This is an offering for multi quantity bundle - 4 count.