Exo Terra - UVB 100 HO T5 Bulb – 3% UVB (Ferguson Zone 1)

Even nocturnal, crepuscular, and shade-dwelling species benefit from gentle, filtered ultraviolet light to truly thrive. At Rachel's Reptile Resource, we believe in elevating reptile care through modern, science-backed husbandry—because cold-blooded companions deserve the same thoughtful care as any other member of the family.

Engineered and made in Germany to meet strict quality standards, the Exo Terra Reptile UVB100 VHO T5 Bulb replicates the gentle solar UVA and UVB rays that filter through dense forest canopies and cloud cover. Featuring a 3% UVB output specifically tailored for Ferguson Zone 1 (the Cryptophotic Zone), this Very High Output (VHO) T5 bulb provides safe, low-to-moderate UV exposure. By supporting natural Vitamin D3 synthesis, it maximizes calcium absorption, promotes strong bone development, and helps prevent Metabolic Bone Disease (MBD)—all while creating a comfortable, naturalistic habitat for your shade-loving reptiles.

Key Features & Benefits

• Tailored for Ferguson Zone 1 (3% UVB): Specifically calibrated for nocturnal, crepuscular, and shade-dwelling ("cryptophotic") reptiles and amphibians that require low-to-moderate UV exposure.
• Supports Essential Physiology: Unique phosphor blend replicates natural solar UVA and UVB rays to drive healthy Vitamin D3 synthesis, maximize calcium absorption, and help prevent Metabolic Bone Disease (MBD).
• German-Engineered Reliability: Manufactured in Germany for superior, consistent, and long-lasting UV output.
• Ideal for Tropical & Bioactive Setups: Pairs seamlessly with naturalistic and bioactive terrariums replicating shaded forest floors or tropical canopies.
• Fixture Compatibility: Fits any T5 HO Fixture.  Including our Vivarium Electronics T5 HO Fixture.

Available Sizes & Standard T5HO Fixture Compatibility

• 8W Bulb: Fits in a standard 12" T5HO fixture
• 24W Bulb: Fits in a standard 24" T5HO fixture
• 39W Bulb: Fits in a standard 36" T5HO fixture 
• 54W Bulb: Fits in a standard 48" T5HO fixture

Keeper Husbandry Note

• Creating a Safe Photogradient: Always position your UVB bulb alongside appropriate overhead heat and plenty of foliage, hides, and branches so your reptile can self-regulate its exposure. Keep in mind that placing a fixture over a mesh screen top will reduce UVI output by roughly 30–45% depending on the mesh density, and UVB bulbs should be replaced every 10–12 months (or checked regularly with a Solarmeter 6.5r) as invisible UV output naturally decays over time.

Equivalency

• Arcadia Equivalent: Arcadia ShadeDweller / ShadeDweller-Arboreal (2.4% – 7% T5) — specifically matching the gentle UV index profile of low-Ferguson Zone 1 setups.
• Zoo Med Equivalent: Zoo Med ReptiSun 5.0 T5HO (used at greater distances) or Zoo Med ReptiSun 2.0 / Low-Output T8 linear equivalents for cryptophotic and crepuscular species.
• Best For: Crested geckos, gargoyle geckos, leopard geckos, mourning geckos, ball pythons, dart frogs, and other crepuscular, nocturnal, or forest-floor dwellers.