Fluker's Sun Glow Coil Bulb for Reptiles and Birds, 20 watt 5.0 UVB In captivity, reptiles that have poor lighting conditions can develop life-threatening diseases. Sun Glow fluorescent bulbs provide essential ultraviolet B radiation for captive reptiles and amphibians Bulbs generate more UVB (&gt; 250 watts/cm) than competitor's 5.0 fluorescent tubes (&gt; 250 watts/cm)! Sun Glow bulbs should be used in combination with Repta-Sun incandescent bulbs which can be used to regulate the environmental temperature. UVB radiation is needed to produce vitamin D