One of the product highlights:
7. Fluorine Coating and Moisture-Resistant Construction for a more user-friendly lens
The front surface of the lens element is coated with a protective fluorine compound that is water- and oil-repellent. The lens surface is easier to wipe clean and is less vulnerable to the damaging effects of dirt, dust, moisture and fingerprints. For greater protection when shooting outdoors, leak-proof seals throughout the lens barrel help protect your equipment.