The Zilla Daylight full0spectrum fluorescent bulb provides high-intensity light output that simulates natural sunlight and enhances the natural beauty of the terrarium and coloration of reptiles. It generates photosynthetic energy to stimulate lush plant growth. Energy efficient bulb lowers energy costs. The T5 full-spectrum bulbs provide visible light output in the 6,700K nanometer range, which helps bring out subtle colors in a reptile"s skin. This bulb is designed to last for 3,500 hours or twelve full months with average use.