Thanks to the protective htc (hydrophobic tech coating) treatment, droplets of water slide from the surfaces, leaving them free of streaks and dirt. This protection makes the lenses more durable and long-lasting, for sharp and defined vision. The htc layer helps the lens stay resistant to dirt, and makes it super smooth and easy to clean. Cressi sunglasses have superior optical quality; they block reflections and protect against uv rays. They offer sharp vision that is rich in detail and increases contrast, protecting the eyes from harmful rays. This combination improves comfort and decreases eye fatigue. The polarizing filter in the cressi sunglasses guarantees sharp vision free of reflections and glare. Cressi polarized sunglasses block harmful sunlight reflected from horizontal surfaces, such as water or a road surface, while allowing vertical light to reach the eye. Vertical light is important for human eyes and improves vision