Ideal for desert reptiles with very high UV requirements UVB helps prevent metabolic bone disease Ideal for desert set-ups or taller terrariums Very high D3 Yield Index Increased Vitamin D3 photosynthesis Maximizes calcium absorption Enhanced UVB penetration distance The Exo Terra Reptile UVB200 emits the ideal UVB spectrum for optimal Vitamin D3 photosynthesis. The Reptile UVB200 Bulb is especially designed to simulate conditions for reptiles with very high UV requirements, like diurnal reptiles from desert environments. These areas receive direct unfiltered sunlight with high levels of UVB. The significantly high Vitamin D3 yield index results in increased vitamin D3 photosynthesis to aid calcium absorption and prevent metabolic diseases. The extended UVB penetration makes this bulb the ideal choice for taller terrariums or terrariums with denser screens. The longer sizes can be placed on multiple terrariums. The packaging includes all necessary information: Full Spectral Graph, UV Spectral Graph, Reptile Bulb Rating System and distance related information like: UVB output - Photosynthesis - Ferguson Zones and Exo Terra Reptile UVB Chart.