What Is ZWB2?

ZWB2 is a special UV-pass, visible-light-blocking optical glass designed specifically for ultraviolet applications.

• Allows UV-A wavelengths (around 365nm) to pass through

• Blocks most visible light from 380–500nm

• Eliminates the “white glow” often seen in unfiltered UV flashlights

In simple terms:

ZWB2 removes everything except the UV you actually want.

Why UV LEDs Need a Filter

Even the best 365nm LEDs produce more than just UV.
They also emit small amounts of visible blue and violet light—a problem known as “contamination light.”

This stray visible light causes issues:

❌ Washed-out fluorescence

Because white/blue spill light brightens the surface.

❌ Lower contrast

Fluorescent minerals, inks, and markings look dull instead of glowing.

❌ Harder to detect fine details

Forensic and inspection work becomes less accurate.

❌ Photos and videos look terrible

The camera captures the unwanted visible light more strongly than your eyes do.

This is why professionals demand filtered UV instead of “bare 365nm.”

How ZWB2 Glass Fixes the Problem

ZWB2 is engineered to block visible wavelengths that UV LEDs accidentally produce.
The filter absorbs:

• Violet light

• Blue light

• Any white-light leakage

While letting the pure 365nm peak pass through almost untouched.

🔬 Result: Truly pure ultraviolet illumination.

Your eye may not see the UV beam—but you’ll see the effects:

• Stronger fluorescence

• Cleaner colors

• Higher inspection clarity

• Better photos and documentation

This is the difference between professional UV lighting and cheap UV flashlights.

What You Notice With ZWB2 (Real-World Results)

✔ Mineral Fluorescence

Colors pop dramatically—greens, oranges, blues appear brighter and more vibrant.

✔ Forensic / industrial detection

Oil traces, dye markings, and security features stand out with higher contrast.

✔ Currency and document inspection

Hidden UV marks are easier to see, even in bright environments.

✔ Resin curing & adhesive applications

More precise UV exposure—no visible light interfering with results.

Once you try a ZWB2-filtered UV light, the difference is instant and unmistakable.

Why UltraFire Uses ZWB2 in Its 365nm Flashlights

Because our customers aren’t hobbyists—they’re professionals who need dependable tools built to perform.

UltraFire integrates ZWB2 glass to:

• Deliver true 365nm output

• Eliminate visible contamination

• Maximize fluorescence clarity

• Maintain a clean, uniform UV beam

• Protect the LED from dust and impact

Combined with our constant-current drivers and high-efficiency UV LEDs, the result is a pure, stable, high-performance UV platform ready for demanding field use.

Who Benefits the Most from ZWB2?

• Mineral hunters & collectors

• UV photographers

• Industrial inspectors

• Security & law-enforcement

• Document verification teams

• Art restorers

• Resin/adhesive professionals

• HVAC technicians & leak detection

• Hotel cleanliness inspectors

If your work depends on seeing precise fluorescence, ZWB2 isn’t optional—it’s essential.

Final Thoughts

A flashlight may say “365nm,” but that doesn’t guarantee purity.
A true, professional-grade UV light must also eliminate visible contamination—and ZWB2 is the key.

By pairing pure UV with the right optics and filtration, UltraFire builds tools that don’t just work—they perform with purpose, clarity, and confidence.

If you’re ready for a cleaner, stronger, and more accurate UV experience, choose a UV flashlight equipped with ZWB2.
Your work—and your results—deserve nothing less.

UltraFire proudly recommends two pro-grade UV lights: the 502UV-Pro (Triple-LED) for wide-area fluorescence hunting, and the RUV3 — a true 365nm UV flashlight with a ZWB2 filter for maximum purity and detection accuracy.