The Exo Terra Night-Glo A19 Moonlight Terrarium Lamp has a dark blue glass sleeve allowing it to emit a moon-like light that provides for nocturnal viewing. The heat generated by the bulb is minimal but enough to provide tropical night time temperatures. The lamp does not interfere with the natural night cycles of the reptiles, and it helps to stimulate breeding behavior in reptiles and amphibians. Reptiles require appropriate and high quality lighting in order to meet certain different metabolic needs. All bulbs are manufactured in colored glass, thereby preventing the fading or cracking as seen in coated bulbs. The Exo Terra Night-Glo A19 Moonlight Terrarium Lamp does not produce UVB rays. It can be combined with Repti-Glo or Sun-Glo bulbs for a 24-hour cycle.