WORLD’S SHARPEST UV FILTER: Our X4 UV features SCHOTT Superwhite B270 optical Glass Made In Germany. Our state-of-the-art multi-resistant coating has 16-layers (MRC16) which increases light transmission to 99.4% and creates a protective layer that’s structurally harder than the glass. The moment you pick up X4 UV you’ll immediately feel the craftsmanship and quality. | TRACTION DESIGN: The X4 UV features an ultra-slim double-threaded 3.2mm Traction Frame which eliminates vignetting and light falloff on full-frame wide-angle setups while still working with all your lens caps. The X4 UV’s double-threaded traction frame will accept all of your filters and existing lens caps. | NANOTEC: In addition to state-of-the-art MRC, our optical engineers developed new nano coating layer technology, called nanotec, from the ground up to repel dirt, water and other elements by beading rather than absorbing and smearing, making it easier (and faster) than ever to clean. | FITMENT: This UV filter is compatible with all 52mm camera lenses. Your lens thread size will be printed underneath your lens cap or written somewhere on the lens barrel. Make sure you order the correct size otherwise it will not fit your lens. | 25 YEARS SUPPORT: We stand behind every UV filter we make with our 25 Year Ironclad Guarantee. Every X4 UV filter has a unique serial number laser engraved onto the interior frame. When you activate your 25 Year Ironclad Guarantee, we assign this serial number to you, so any future discussions on this unique filter are tracked, issues recorded and all that stuff which goes into future product design.