Premium incandescent light fixtures are designed to deliver years of heat or light to reptile terrariums. Each of the sizes is topped with a ceramic socket to withstand constant heat. The 8.5" fixture accepst bulbs to 150 watts, the 10" up to 250 watts. The black exterior finish is powder coated and fired for added luster and long life. An in-line on/off switch is positioned near the fixture for easy use.