Light-reduction Coating Aeronautic Aluminum Fast Attachment Protection of Original Filter UV Filter: The UV filter also called ultraviolet filter, mainly prevents UV light from entering the camera, avoiding blue light from affecting the images, at the sea, mountains, and other open areas, where the light can be bluish or whitish. Using the UV filter in high mountains or altitude, increases the distance field of the shot and makes for a clear shot. It also provides protection to the camera. SCHOTT Optical Glass: Uses German SCHOTT glass as its base material utilizing multiple grinding and polishing processes. Light-reduction Coating: Light-reduction coating saves ND filter from discoloration. Double-sided and Multilayer Coating: Nanometer-scale, double-side, multi-layer vacuum coating process ensures a first-class waterproof, oil-proof, dust-proof, and anti-scratch protector. Fast Attachment: Directly attach the filter to ensure its anti-water and anti-dust capacity, which can be damaged by replacing the original filter. Aeronautic Aluminum + Knurling Pattern: Made of aeronautic aluminum, the frame features a knurling pattern to ensure quick attachment. Protection of Original Filter: The inside part of the frame is covered with silica gel to protect the original filter from being scratched during attachment. Specifications: Dimensions: 36.5 x 36.5 x 7.85 mm Weight: 3.8 g | PGYTECH Osmo Action UV Filter