Fluker's Premium Heat MatProvide evenly distributed heat at a constant 100 degree temperature, which help them regulate core body temperature. Safe for all reptiles and amphibians Small size may be used inside or outside of 10 to 20 gallon terrariums Medium size may be used inside or outside of 20 to 30 gallon terrariums Large size may be used inside or outside of 30 to 40 gallon terrariums