Day Blue Light Incandescent Bulbs provides basking heat source for reptiles to regulate their body temperature Emits full-spectrum light and UVA rays needed for a healthy reptile environment. Ideal for tropical and desert habitats; the day blue lamp generates a gentle blue light that enhances the color of reptiles while providing a heat source needed for a healthy reptile environment. The uncoated blue glass allows the bulb to transfer more heat to the reptile enclosure, allowing the reptile to bask in its warmth.