The bulb simulates natural moonlight to allow nocturnal viewing without disturbing the animal's day and night cycle. The light emitted is bluish due to the use of blue glass. The heat generated by the bulb is minimal but enough to provide tropical night time temperatures. The lower wattage of these bulbs does not interfere with natural night drops in temperature.  Moonlight lamp  Simulates natural moonlight  Perfect for nocturnal viewing  Provides tropical night time temperatures  Stimulates breeding behavior in reptiles and amphibians  Can be combined with Repti Glo or Sun Glo for a 24 hour cycle.