Most "UV flashlights" are a party trick — a purple LED that makes white shirts glow and washes everything else out in visible violet light. Real ultraviolet work happens at 365 nanometers, and the difference is night and day: minerals fluoresce in colors you didn't know they had, pet stains appear on a floor that looked clean, resins cure properly, and security marks show up crisp instead of drowned in purple glare. This is the guide to doing UV right.
365nm vs 395nm: why the number matters
Cheap UV lights run 395–405nm emitters because they're inexpensive. The problem: at 395nm a large chunk of the output is visible violet light, which floods the very fluorescence you're trying to see. A true 365nm emitter sits deep enough into the UV-A band that the beam itself is nearly invisible — so the only thing your eyes see is the glow coming back. Once you've compared them side by side, you can't go back.
The ZWB2 filter: the other half of the trick
Even a genuine 365nm emitter leaks some visible light. A ZWB2 filter is a piece of Wood's glass that swaps in place of the regular lens and blocks that leakage — the beam goes fully "black light," and fluorescence contrast jumps dramatically. We stock filters cut for each host: S2+, S12, and T2/T3. If you buy one accessory for a UV light, this is it.
Picking your UV light
Dedicated 365nm instruments
- Convoy T2 UV and T3 UV — pocket-sized AA/14500 lights; the cheapest way into real 365nm.
- Convoy S2+ UV — the classic 18650 host with a Nichia 365nm emitter; serious output, familiar body.
- Convoy S12 UV — three 365nm emitters on a 21700 cell. This is the mineral-hunter's light; rocks light up across the room.
- Convoy L21B UV — a thrower-sized reflector behind a 365nm emitter, for UV at distances no pocket light reaches.
- Nitecore GEM10UV — purpose-built for gem and mineral inspection, with adjustable UV intensity.
White light first, UV included
- Nitecore P20UV V2 — a full 1000-lumen tactical light with auxiliary UV emitters; one light for patrol and document checks.
- Fenix E06R — 700-lumen EDC with UV and a red laser tucked in.
- Nitecore EDC17 — flat EDC powerhouse with UV and green laser on board.
- Nitecore Thumb Leo — a clip-on work light with UV for quick checks.
- CipherLight 1000 — white, UV, and RGB in one pocket light.
Brute force
The 120W six-LED 365nm floodlight is for curing large resin pieces, scanning whole rooms, or lighting up a rock face. Subtle it is not.
What people actually use these for
- Rockhounding — fluorescent minerals (calcite, fluorite, willemite, hyalite opal) glow electric colors under 365nm. This hobby alone justifies the S12.
- Pet stain and cleanliness detection — dried biological stains fluoresce. Hotel rooms become horror movies; your carpet becomes honest.
- Resin and adhesive curing — UV-cure resins set faster and harder under strong 365nm.
- Verification — security threads in currency, ID features, and event-stamp checks all read cleanly at 365nm.
- Scorpions — they fluoresce blue-green. You will find more of them than you hoped.
- Invisible marking — the UV invisible ink pen writes marks only a UV beam reveals; label gear, mark property, leave notes.
The easy button
If choosing parts isn't your idea of fun, we pre-assembled the two setups we'd build ourselves: the S2+ UV Master Bundle (light, ZWB2 filter, cell — the complete starter instrument) and the S12 UV Master Bundle for triple-emitter power out of the box. Everything ultraviolet lives in the UV flashlights collection.
One safety note: 365nm is still UV-A. Don't stare into the emitter, don't point it at anyone's eyes, and take it easy on bare skin at close range during long curing sessions. Respect it like sunlight, because that's what it is — concentrated.