Utilizing a new patented HMC nano-coating process that applies 32-layers of anti-reflective (AR) coating to its optical ultra-violet (UV) glass, Hoya created a filter that is 5x sharper and a coating that is 800% harder than the award-winning HD2 UV filter. The HD3 filter yields a light transmission rate of 99.7% and uses the same chemically enhanced 4x harder optical UV glass that made the HD2 filters. “The Toughest Filters on the Planet.” The new coating process created a top layer that is more scratch & stain resistant, and water & oil repellant, making it easy to clean when smudges and fingerprints are introduced to the surface. 4x Harder Optical Glass than traditional filter glass Re-Certified Resolution for 100mp+ Cameras 800% harder surface resists scratching and abrasions Patented Ultra-hard Nano-coating process Superior Resolution and Sharpness Waterproof and Stain-resistant top coat makes it easy to clean Lifetime Limited Warranty