Exo Terra reptile UVB150 emits optimal amounts of UVB; Similar conditions in shady environments such as rainforests or other tropical sites. The reptiles that live in these habitats receive moderate amounts of UV radiation due to the climatological conditions (rather high humidity, weather changes, etc.). This prevents unfiltered sunlight to hit the sunbathing reptiles. The optimal vitamin D3 advantage index ensures vitamin D3 photosynthesis, which contributes to calcium absorption and protects against the softening of the legs