The Zilla Pro Series UVB/UVA Bulbs give out high levels of UVB and UVA which are required for animals with high UVB needs and benefit all living species. When it comes to the health of your reptile, the UVB light provided by a Desert 50 Bulb (50 microwatts per second/cm2) is as essential for long term wellness of your desert or high UVB needs reptiles. Tropical 25 Bulbs provide tropical species with a full dosage of UVB (25 microwatts per second/cm2) along with essential UVA light. Zilla Pro Series bulbs are designed for 3500 hours or twelve full months of average use. Provides UVB light rays which are required for many reptiles to metabolize essential calcium|Full spectrum lighting enhances natural colors of the animal and environment|Energy efficient bulb which lowers energy costs (replace every 12 months to ensure proper UVB levels)|Coil bulb design fits most standard incandescent bulb sockets br/>Sold in Quantity of: 1