Zilla UVB Fluorescent Bulb 18 inch Desert Series 50 T8 bulb is ideal for desert dwelling reptiles that require UVB/UVA lighting Provides UVB light rays which are required for many reptiles to metabolize essential calcium Full spectrum lighting enhances natural colors of the animal and environment Replace every 12 months to ensure proper UVB levels Recommended for use with Zilla T8 Strip Light Fixtures