Photochromic lenses 2-4 are special photochromic lenses with a basic smoke color that can reach category 4 at maximum functionality. The starting color is a very light smoke, allowing for clear vision even in areas with deep shadows or very low light. During maximum exposure to optimal light and UV conditions, the lens reaches category 4, making it ideal for mountaineering and flying sports to provide maximum eye protection at high altitudes.

Like common photochromic lenses, the 2-4 photochromic lens, when exposed to UV radiation and sunlight, triggers a reversible chemical reaction that darkens the lens surface, reaching category 4 when needed. Once UV exposure ends, the lens gradually returns to its original light state.

Sports where the 2-4 photochromic lens can be used:

• Mountaineering and Hiking: This special photochromic lens was designed with the mountain environment in mind, where UV intensity and light rays are stronger. It offers dynamic adaptability for hikers and mountaineers, adjusting to every change in light conditions along the path. Whether entering a forested area or a shaded slope, the lens lightens and darkens quickly, allowing athletes to maintain constant and perfect vision.

The starting color is a light smoke tint, so there's no need for athletes to remove the glasses in low-light conditions. Category 2 prevents glare when emerging from shaded areas, while the lens reaches category 4 at peak exposure, depending on the intensity of UV rays and sunlight. This special lens is designed to reach category 4 only when necessary, preventing the view from becoming too dark.

It can also be used in place of a standard category 4 lens for extreme expeditions (like Everest or K2), as it provides the same level of protection but dynamically adapts to changes in light.

Paragliding, Hang Gliding, and Flying: Due to the same factors mentioned earlier (more intense UV rays and light intensity at higher altitudes), the 2-4 photochromic lens is also suitable for flying sports. It is highly effective against light glare and adapts quickly to changes in light, making it a very relaxing lens for the eyes, even with prolonged use. It provides maximum comfort and relaxation.

It is important to note that this lens is not suitable for use in airplanes (e.g., piloting tourist planes or gliders), as the glass shielding prevents the chemical reaction of the lens, since UV rays are blocked by the plane's glass. In such cases, we recommend choosing a category 4 lens.

Lens Materials and Features: The 2-4 photochromic lenses are made from high-quality, shatterproof polycarbonate. The impact resistance of polycarbonate is crucial because, in the event of an accidental impact, the lens does not create dangerous fragments that could harm the eye. Instead, it distributes the impact across its entire surface, forming a spider web-like effect, rendering it unusable but safe. The lightness of polycarbonate also enhances both performance and comfort. Additionally, the lenses are decentralized and optically perfect, which provides accurate depth perception and prevents feelings of dizziness or discomfort that can arise from using curved lenses or those with incorrect decentration.