This fixture is able to provide for UVB and basking requirements in one streamlined fixture that is also easy-to-mount underneath your cage’s top screen mesh; patent-pending, made in U.S.A. This T5HO (high output) fixture gives superior performance because of its high output electronic ballast and its high-efficiency silver reflector. UVB is necessary for your reptile’s synthesis of vitamin D3, which is essential for the effective metabolism of dietary calcium in its bones and blood. We prefer the UVB output from linear fluorescent tubes because this way it’s possible to cover 2/3’s of the habitat area; ensuring that the reptile is benefiting from some UVB exposure as it moves about the habitat. The basking socket uses energy-efficient halogen bulbs; typically 50 watts (20L habitats) or 75 watts (40B habitats and our Custom Cages). This fixture with the appropriate UVB fluorescent tube is a superior addition to the habitats of bearded dragons, Rankin dragons, horned toad lizards, uromastyx, most other desert reptiles, small turtles and tortoises. Animal should be no closer than 10” directly under the fixture and no closer than 6” diagonally from the sides or ends of the fixture. Also, take care that your pet cannot touch the halogen basking bulb, when you arrange your habitat accessories. We do sell both the Zoo Med ReptiSun 10.0 UVB T5HO and the 5.0 UVB tubes for this fixture; plus 20w, 35w, 50w and 75w halogen basking bulbs. Carolina Custom Cages is a division of Carolina Designer Dragons, Inc.