For Extreme Conditions, 99% Transmittance with Low Reflection, Two-Toned Brass Frame with Knurling, Front Filter Thread. The 43mm Armor FX PRO Nano L395 UV Protection Filter from NiSi is designed to withstand extreme conditions including heavy impacts such as hammer blows. It protects your lens against dust fingerprints dirt scratches sand and seawater spray. The filter's optical glass features double-sided low reflection and nano coating that makes it waterproof and oilproof and easy to clean. It allows high light transmittance with neutral colors and no loss in sharpness even when using high-megapixel sensors. The filter frame is made of brass and has an ultra-slim two-tone construction with knurling for easy gripping and it features a front filter thread.