Julbo Lenses: Understanding Each Technology (REACTIV, Alti Arc, Spectron)

Julbo designs lenses crafted for adventure. On Visionet, we offer the full range: you can filter by lens type (REACTIV, Alti Arc, Spectron, polarized…) to quickly find the model suited to your activity. We are among the best Julbo sellers in France – wide selection, availability, and clear advice.

0Julbo Lenses Summary (18 variants)

REACTIV 0‑4 High Contrast

Range 0→4 (night→glacier). Enhanced terrain reading, anti-fog. A single versatile lens.

REACTIV 2‑4

Versatile mountain. Brown base enhances terrain. Fast photochromic 2→4.

REACTIV 2‑4 Polarized

High mountain + polarization. Cuts glare from snow/water.

REACTIV 2‑3 Glare Control

Slightly polarized, screen-compatible. Trivex material.

REACTIV 1‑3 High Contrast

Enhanced contrast for technical terrain. Ideal for trail/MTB.

REACTIV 1‑3 Light Amplifier

Boosts brightness in overcast weather. Remains comfortable in sun.

REACTIV 0‑3 High Contrast

From night to midday. Anti-fog. Perfect for very early morning outings.

REACTIV 1‑3 Glare Control

Moderate polarization, readable screens. City/road/freshwater.

Alti Arc 4 (mineral)

Cat. 4 very dark. Highly scratch-resistant. Glacier reference.

Spectron HD 4 Polarized

Cat. 4 + ~80% polarization. Sea and extreme light.

Spectron HD 3 Polarized

Contrasted daily use. ~80% polarization, screen-compatible.

Spectron HD 3

Cat. 3 fixed tint. Enhanced colors. Strong sunlight.

Spectron 3 Polarized

Eliminates water/snow/asphalt reflections. Cat. 3. Multi-purpose.

Spectron 3

Light and solid polycarbonate. Cat. 3. Mirror finishes available.

Spectron HD 1

Low light/end of day. High comfort.

Spectron 4

Cat. 4 very dark protection. Extreme sun. Not recommended for driving.

Polar Junior

Polarization designed for children. Comfort & robustness.

1REACTIV Lenses (photochromic)

REACTIV lenses automatically darken and lighten according to the light. Ideal when the weather changes, or when moving from shade to full sun without stopping.

REACTIV 0-4 High Contrast

Ultra-wide range (UV0→UV4): from 100% translucent to very dark. Gray base with variable red mirror; increased terrain reading and effective anti-fog for intense efforts. A single lens for night, dawn, and glacier. Ideal for early morning outings, forest/clearing transitions, or alpine routes where the weather changes quickly. The tint change is progressive and fast, avoiding the need to remove glasses in tunnels or undergrowth, while offering excellent protection at the summit.

TLT ≈ 86% → 4%* | Cat. 0 to 4 | Anti-fog & oleophobic. Excellent helmet/mask compatibility.

View modelsPhotochromicHigh Contrast

REACTIV 2-4

Designed for the mountains: cat. 2→4 transition, brown base to highlight terrain and choice of flash mirrors. Clear vision in full sun as well as under cloudy skies, without changing glasses. Fast transition for valley approaches, snowfields, and exposed ridges; perfect for summer mountaineering, high-route trekking, and high-altitude gravel biking.

TLT ≈ 35% → 7%* | Anti-fog + oleophobic. Lasting comfort on long days, simplified maintenance.

View modelsMountainPhotochromic

REACTIV 2-4 Polarized

The high mountain reference: photochromic 2→4 + polarization (≈99%) to cut glare from snow and water. Enhanced contrasts, relaxed vision on long outings. Ideal for ski touring, glacier expeditions, and offshore sailing where glare is constant. Anti-fog/oleophobic treatments keep lenses clean despite wind, powder, and perspiration.

TLT ≈ 20% → 5%* | Anti-fog + oleophobic | Brown base, dark mirror. Chromatic stability without color distortion.

View modelsPolarizationHigh altitude

REACTIV 2-3 Glare Control

Photochromic & slightly polarizing (~85%) lens: reduces reflections while remaining screen-compatible. Trivex material: very light, clear optics, high resistance. Excellent "all-terrain" option for running, mountain biking, coastal sailing, and daytime driving where GPS, watches, and meters are frequently consulted.

Cat. 2 to 3 | Variable TLT* | Ideal for sport & daily use. Trivex: clarity close to mineral, featherlight.

View modelsGlare ControlTrivex

REACTIV 1-3 High Contrast

For technical terrain: pink/brown base that accentuates relief, blue mirror, and cat. 1→3 transition. Impeccable terrain reading from shaded trails to full sun. Ideal for trail running, enduro, and fast hiking where contrast is key to spotting roots, rocks, and ruts.

TLT ≈ 72% → 13%* | Anti-fog + oleophobic. High visual comfort during prolonged efforts.

View modelsTrail / MTB

REACTIV 1-3 Light Amplifier

Designed to boost brightness when it's lacking, while still reaching cat. 3 when the sun returns. More readable details, more vibrant colors. Perfect for dense forests, changing weather, urban sports at dawn/dusk, and low winter days.

TLT ≈ 75% → 17%* | Anti-fog + oleophobic. Reduces eye fatigue in low light.

View modelsVersatile

REACTIV 0-3 High Contrast

From night to full day (cat. 0→3). Gray base + subtle red mirror; accentuated contrast and anti-fog treatment to keep the lens clear in all circumstances. Ideal for very early morning outings, urban running with tunnels and shaded areas, or bike commutes.

TLT ≈ 87% → 15%*. Smooth transition, no "on/off effect".

View models0→3

REACTIV 1-3 Glare Control

Photochromic 1→3 with moderate polarization (~56%): cuts glare without hindering screen reading (GPS, meter). Finishes include copper base + rose mirror or gray base + silver mirror. Excellent choice for city, road, and freshwater sports where instrument reading and light variations alternate.

TLT ≈ 46% → 10%* | Oleophobic. Natural vision, minimal distortion.

Screen-compatible

2Alti Arc 4 Mineral Lenses

Alti Arc 4

The choice for high altitudes. Very dark mineral cat. 4 lens, often with a brown base to improve terrain reading. Excellent scratch resistance, anti-reflective and hydrophobic treatments to maintain clear vision even amidst wind, snow, and splashes.

Category 4 | Maximum protection (not recommended for driving) | Ideal for glaciers and strong glare.

View modelsMineralGlacier

3SPECTRON & SPECTRON HD Lenses

Polycarbonate lenses: lightweight, impact-resistant, and available in polarized versions as needed.

Spectron HD 4 Polarized

Cat. 4 polarized (~80%) to cut reflections on water and snow. Dark tint (low TLT) with blue mirror depending on model and hydrophobic treatment.

Category 4 | TLT ≈ 7%* | Sea & high light.

Polarized

Spectron HD 3 Polarized

Clear and contrasted daily vision: ~80% polarization, screen-compatible, hydrophobic treatment, and mirror depending on versions. UV protection cat. 3.

Moderate TLT* | Unbreakable polycarbonate.

DailyPolarized

Spectron HD 3

Fixed cat. 3 tint for strong brightness, enhanced color rendering, and contrast specific to the HD series. Hydrophobic to repel water.

TLT ≈ 15%* | Ideal for cycling, sunny city.

Spectron 3 Polarized

Polarizing to eliminate glare (water, snow, asphalt) with cat. 3 protection. Good multi-purpose companion.

TLT ≈ 12%*.

View modelsPolarized

Spectron 3

Cat. 3 polycarbonate, lightweight and resistant. Available with mirror finishes for style and anti-glare.

TLT ≈ 13%* | Sport & urban use.

View modelsPolycarbonate

Spectron HD 1

Soft tint for low to variable light (end of day, changing weather). High visual comfort and impact-resistant materials.

Category 1 | TLT ≈ 45%*.

Low light

Spectron 4

Cat. 4 protection for extreme light (high mountains, very bright beach). Very dark; not recommended for driving.

Very low TLT* | Lightweight & resistant.

View modelsCat. 4

Polar Junior

Polarized version for children: reduces glare and improves visual comfort during outdoor activities. Designed for daily resistance.

Polarizing | Designed for young users.

Child

4FAQ – Julbo Lenses

REACTIV, Spectron or Alti Arc: what are the differences?

REACTIV: photochromic, they automatically adapt their tint (ideal when light varies). Spectron: fixed polycarbonate (with or without polarization), light and robust for sport and daily use. Alti Arc: very dark cat. 4 mineral lens for extreme sun and strong glare (glacier).

Which lens for high mountains/glaciers?

Alti Arc 4 or REACTIV 2-4 Polarized: maximum protection and glare management on snow. Spectron 4 also suitable, but without the adaptability of REACTIV.

Category 4 and driving: is it allowed?

No, category 4 lenses (very dark) are not recommended for driving as they significantly reduce light transmission. Opt for cat. 2–3 (or REACTIV which lighten).

Polarization: screen-compatible?

Strong polarization can darken or cause some screens to shimmer. Choose REACTIV 2-3 Glare Control (~85%) or REACTIV 1-3 Glare Control (~56%) to maintain good readability of GPS/meters.

REACTIV lens change speed?

The transition occurs in a few seconds and continuously adjusts according to UV and temperature. The advantage: you keep your glasses on permanently, from undergrowth to full sun.

How to choose on Visionet?

Use our filters by lens type (REACTIV 2-4, Alti Arc, Spectron 3 Polarized, etc.). You can also sort by activity (trail, MTB, mountaineering, sailing) and by color/mirror. Need help? Contact us, we'll guide you according to your use.

* Light Transmittance (TLT) values are indicative according to manufacturer documentation and may vary slightly depending on color and mirror treatment.

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