This is a RATING REVIEW for the item for sale on Amazon with description: K&F Concept Nano-K Magnetic Filter, CPL Circular Polarizing Filter made of Optical Glass with Nano Coating for 77mm Lens (Includes a Cleaning Cloth). This is a CPL filter (polarized light control by turning on its axis) very comfortable to use thanks to its two-piece system: threaded anchor ring and filter with magnetic outer ring, the threaded ring is installed and then it can be removed with a simple grip and pull of its contour (which has a ridged texture for a better grip) and to fix it again, present it to the ring and position it until you notice the magnetic pull and its anchor in a well-aligned position. As for the benefits, they are noticeable outdoors with good sunlight (indoors and artificial light it is not noticeable and in very shaded outdoors either, so it is usually used in landscape shots, especially those where an area of sky or clouds appears or where there is a reflection of light in rivers, springs, lakes, etc ... or with metallic effect reflections. Depending on the orientation in which the ring is turned, the image becomes darker or lighter a little, attenuating the sunlight and taking more or less color saturation (when turning it on the magnetic system it has a little sound like a squeak of friction, but as it is normally used in photography and video, the position is first searched for and then the recording is activated, it does not affect the audio of the recordings. I have made an edited video with some image changes on the same shots only by partially turning the CPL polarizing ring. The images appear with a greater color tone but less luminous, for this reason it is advisable to retouch the gain of the exposure meter a little, since when turning the ring if we are in manual mode with reference to this or in the preference modes aperture or speed control varies the shooting speeds or diaphragm openings respectively, and I personally like the images a little more vivid, both colors and luminosity, but without annoying reflections. Due to its very good price / quality ratio and its ease of installation and exchange with filters of the same system "Magnetic adapter ring" magnetic fixing ring, its thinness of support "Slim" that prevents vignetting in angular lenses, its good presentation in a protective box and the special cleaning cloth included in the set my rating for this K & F concept filter is: " 5 STARS " = [ * * * * * ] . I hope you find this review useful, Greetings. The drawback that I forgot to mention and noticed later is that on CANON lenses with the front caps of the EF range, these are not held either with the filter installed or with the filter ring with the filter removed, as the filter is narrow format (SLIM) the support tabs of the front lens cap do not engage the profile of either the filter or its support ring, so in order to put the cap on you have to also remove the threaded ring and store the set in its box.