WORLDS SHARPEST AND MOST COLOR NEUTRAL ND: From the moment you pick up X4 nd filter you’ll immediately feel the craftsmanship and quality. X4 52mm nd filter maintains a very well controlled and flat transmission all the way throughout the visible spectrum and into IR, delivering the worlds most color neutral results. | MRC16 OPTICAL COATING: 16 Layer Multi-Resistance Coated to significantly reduce lens flare and ghosting while making the filter Anti-Scratch, Reduce Reflection, Water Repellent, Increase Surface Durability, Oil & Dust Resistant. All these fantastic attributes are essential for working effectively outdoors. Our proprietary MRC coating is structurally harder than the glass itself and the reduced reflections improve the efficiency since less light is lost. | 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. Set in our workhorse and built to withstand extreme wind, salt water, dust and other abrasive conditions and elements. | FITMENT: Our X4 3stop nd 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: This lens filter is guaranteed to be free from craftsmanship defects for 25 years. When you activate your 25 Year Ironclad Guarantee online we associate your X4 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.