Please note I’m not an expert and nor do I own any equipment that can test the manufacture’s claims. I can only compare my experience with this filter vs my Hoya and B&W filters. I got the 58mm filter. The filter come in a semi-hard case. The filter kit includes a micro fiber cloth, pinch lens cap, and lens cap tether. The filter was clear and I didn’t notice any blemish in the filter. It threaded onto my Olympus 75-300mm II lens without any issues. Usually cheap filter can cause extra flaring or ghosting in your image when you have a strong light source. I took a several test pictures of different light sources and I did notice a very minor flaring/ghosting in the image if pointed just right at the light source. Another issue that cheap filters can cause is poor autofocus or decrease in image sharpness. I did not notice any of those issues. I did not notice any vignetting with this filter in place. K&F Concept sells several different UV filters. This is their basic filter which has 18 multi-layer coating but (according to their marketing material) is not Waterproof or Scratch-Resistant. K&F Concept does sell pricier UV Filters that will provide those features if you need them. For the low cost these sell for, I don’t feel you can go wrong with this filter if you want a basic UV Filter to protect your lens.