Reptile Systems Zone 4 T5 1150mm (46") - 54wA fluorescent light bulb that provides UVB to your pet so they can generate Vitamin D3 and absorb calcium from their diet. 55cm length Ideal for desert and arid setups High UBV and UVA output Simulates natural light 12% UVB 30% UVA Natural colours Up to 1 year of productive life This product will only work if used with the correct T5 electronic ballast.