This lamp provides your reptile with UV radiation (A and B) and light visible to the human eye. UVB: Reptiles need UVB for the production of vitamin D and for calcium metabolism. Without UVB, reptiles can develop a collision alternate disease in less than six months. In combination with the right temperature, this lamp ensures that your reptiles produce vitamin D and absorb calcium from their food. UVA: UVA is part of the rainbow of colors that reptiles can perceive. It increases activity level, appetite and stimulates reproductive behavior. Without UVA, reptiles are color blind. The T5 lamps are twice as strong as standard Reptisun lamps.