X1 UV (Ultra Violet) FILTER: The X1 UV features 4-layers of our state-of-the-art and uniformly applied MRC, which means less flaring and ghosting that you’d normally see with uncoated protection filters. Our modern coating chambers are air tight, producing a uniform coating visible to the human eye when holding the filter at a right angle to a direct light source. | MRC4 CONSTRUCTION: Two layers of MRC are applied to each side of the optical disk, resulting in a total of 4 layers (MRC4). In addition to being structurally harder than the glass itself, our MRC coating process increases light transmission from 94.6% (without MRC) to 97.8%. Glass without MRC coatings is highly susceptible to a range of optical phenomenon such as flaring, ghosting (lower contrast as a result) and generally less saturation. | ELIMINATES VIGNETTING: The X1 features a 3.5mm ultra-slim double-threaded frame profile to eliminate vignetting on wide-angle full-frame setups. In our lab tests, 4.2mm was the frame width at which point 1-stop of light falloff (vignetting) became visible on images with 16mm wide-angle setups on full-frame cameras. | X1 UV 77mm FITMENT: The X1 UV has front-threads, which means it’s compatible with all your existing filters (for stacking) and lens caps. To ensure the lettering on the filter never wears off we laser engrave text into each aluminum frame rather than use paint-based lettering. | 25 YEARS SUPPORT: We laser engrave each X1 UV with a unique serial number. When you activate your 25 Year Ironclad Guarantee online we associate your X1 serial number to you, so any future discussions regarding your X1 UV are tracked, issues recorded, all of which goes directly into our design and prototyping pipeline.