The Exo Terra Reptile UVB 100 is a compact fluorescent bulb with a moderate to high UVB output, matched to shaded environments such as rainforests and other tropical habitats. Reptiles from those places get less UV than desert species — high humidity, cloud cover and dense canopy all stand between them and direct sun — so a desert-strength bulb is more than they need.

Why UVB Is Not Optional

This is the single most important thing to understand about keeping reptiles indoors. Reptiles use UVB to manufacture vitamin D3 in their skin, and without D3 they cannot absorb dietary calcium — no matter how much calcium you dust onto their food.

The result of getting this wrong is metabolic bone disease: soft, deforming bones, tremors, a rubbery jaw, and eventually death. It is among the commonest causes of illness in captive reptiles and it is almost entirely preventable.

Note that glass and plastic block UVB. A window will not do it, and a bulb mounted outside a glass lid is doing nothing at all.

Key Features

• Ideal for all tropical and sub-tropical reptiles
• High UVB output, effective up to 30 cm (12 inches)
• Provides the UVB needed for calcium metabolism
• UVA radiation stimulates appetite, activity and reproductive behaviour
• Self-ballasted — a regular screw fitting is all you need
• Spiral shape mounts vertically or horizontally without losing performance
• Available in 13W and 25W

Specifications

Setting It Up

• Mount inside the enclosure, or above an open mesh top. A dense screen can filter out up to 50% of UVB — if yours does, move the bulb closer or step up to the UVB 150.
• Position so your reptile can reach within 30 cm of the bulb at its basking spot, and can also move out of range. Being able to choose is part of how reptiles regulate their own exposure.
• Fluorescent bulbs do not provide meaningful heat. You still need a separate basking lamp.
• Pair with a high visual-output bulb such as the Natural Light for a brighter, more natural-looking terrarium.

Replacement

Replace every 6 months, or as the manufacturer advises. UVB output falls away long before the bulb stops giving visible light — a bulb that still looks perfectly bright can be producing almost no usable UVB. This catches out a great many keepers, and it is worth writing the fitting date on the base of the bulb.

Safety

• Do not look directly into the bulb.
• Always provide a shaded area so your reptile can move out of the UV.
• Let the bulb cool completely before handling.