Night Black Heat Incandescent Bulbs Boxed. Provides 24-hour ambient heat source for a healthy reptile environment Great for night-time viewing to observe natural nocturnal behaviors Ideal for tropical and desert habitats; the bulb provides ambient heat in which the photons emitted by the filament never escape the dark tint, heating the air inside the enclosure to create the warmth needed for a healthy reptile environment. The bulb is made from glass containing rare earth black phosphors, which simulates the moon's natural glow for nocturnal viewing without disturbing the reptile's day/night cycle.