Zoo Med Reptisun T5 HO 5.0 UVB High Output Bulb offers an increased UVB and brighter light output thats perfect for larger reptile habitats. Measuring just 5/8" in diameter, this lamp doesn't take up valuable space, but is still twice as strong as standard 5.0 UVB bulbs. High output UVB bulb thats perfect for larger reptile habitats Emits beneficial UVB up to 24" from the surface of the bulb Provides valuable UVA, UVB and visible light Stronger and brighter light; twice as strong as standard ReptiSun 5.0 lamps Helps prevent or reverse Metabolic Bone Disease Used and recommended by zoos, veterinarians and top reptile professionals This bulb emits 30% UVA and 5% UVB, as well as full-spectrum visible light. Zoo Med ReptiSun 5.0 UVB T5 HO High Output Bulb is for use in lighting fixtures rated for T5 HO (High Output) lamps. Ideal for large habitats with the following reptiles. Tropical Lizards (Green Iguanas, Day Geckos, Anoles, Water Dragons). Aquatic Turtles, Box Turtles and Tortoises. Old World Chameleons (Panther Chameleons, Veiled Chameleons, Jacksons Chameleon, etc). This lamp provides UVB, UVA and Visible light for your reptile: UVB: Reptiles need UVB for vitamin D production and calcium metabolism. Without UVB, reptiles can develop Metabolic Bone Disease in 6 months or less. This lamp, along with proper temperatures, will enable your reptiles to make vitamin D and process calcium from their diet. UVA: Reptiles and amphibians can see things that humans can't. UVA is part of the rainbow of colors that reptiles can see. UVA helps to increase activity levels, appetite, and reproductive behaviors. Without UVA, they are color blind! Lamp Fixture: For use in fixtures rated for T5 HO (High Output) lamps. For best results, use Zoo Meds ReptiSun T5 HO Terrarium Hood. Lamp Distance: Refer to the back of your lamps box for optimal UVB emit distance (15W - up to 18"). Glass and plastic filter out UVB; there should be no glass or plastic between the lamp and your reptile. Fine mesh blocks up to 50% of light and UVB. This should be taken into consideration when determining lamp distance. The T5 ReptiSun HO is designed for most reptiles housed in terrariums that are 12" to 18" tall. Always have a lamp at least 6" away from your animal. The optimal distance from T5 HO lamps to the animal is 12-24", depending on the lamp. When To Replace Your Lamp: This lamp will provide your animals with beneficial UVB for a period of 12 months when used 10 to 12 hours per day. Record date of first use of lamp and replace after 12 months.