Zilla Desert 50 UVB bulbs surpass the competition by producing more UVB towards the wavelengths where vitamin D3 is most effectively synthesized. This allows you to provide your reptiles with the UV light they require. Zilla Desert 50 UVB bulbs also have a superior UVA to UVB ratio very similar to natural sunlight to create a comfortable, natural environment for your reptile. UVB light output promotes proper calcium absorption for desert reptile bone health. The Desert Series Low Profile T5 Fixtures combine a fixture and bulbs in one convenient package, and fits in tight spaces as they are only 1" high. They feature a built-to-last sleek black-aluminum housing with UVT acrylic lens and a highly polished reflector. Single Bulb Fixture includes a Desert 50 T5 fluorescent bulb with a UVB output of 50 microwatts per second/cm2 @ 12".