The Exo Terra Reptile UVB200 emits the ideal UVB spectrum for optimal vitamin D3 photosynthesis. The Reptile UVB200 bulb has been specifically designed to simulate conditions for reptiles with very high UV requirements, such as diurnal reptiles from desert regions. These areas receive direct unfiltered sunlight with a high UVB content. The significantly high yield index of vitamin D3 leads to increased photosynthesis of vitamin D3 to support calcium absorption and prevent metabolic diseases. The extended UVB penetration makes this lamp the ideal choice for larger terrariums or terrariums with denser screens.