K&F Concept is synonymous with quality. I already had other filters of theirs, even though they were quite old and with several years of service behind them. In light of an upcoming photographic trip of mine, I decided to opt for something new, always relying on them. I will tell you in detail what, in my opinion, are the pros and cons of this new product of theirs. First of all, the packaging is really excellent: the box is made of very sturdy cardboard, impossible to fold, and the magnetic opening is very pleasant. The filter is stored in a leatherette case with a magnetic closure and not in plastic, which gives the product a finish that we can define as "premium". Inside, wrapped in a protective bag, the filter. It is a fairly heavy piece, but it already gives an excellent impression to the touch. The body is made of aluminum, the glasses are of excellent finish. Very thin (and this is a good thing because this reduces any loss of sharpness), waterproof and scratch-proof. Very nice (and very useful!) the orange thing that is used to vary the intensity of the filter itself: the only flaw is that it does not have a limited stroke during rotation, but it is not a big problem, since the ND2 and ND400 limits are indicated right on the end of the filter itself. In any case, the filter has been built in such a way that, even when exceeding the limits, the annoying "X" shadow does not appear. For the moment I have only had the opportunity to try it in the city on a somewhat gloomy day, in the next few days I hope to integrate this review of mine with other shots in the mountains. Who is the filter aimed at? Certainly those who love landscape photography or those who want to take long exposures in the city (staying within the limits of 9 stops): of course, the product is not the cheapest on the market, but you just have to try it for a while to understand that it is worth every cent spent. I am not a photography professional, but for my use it is more than enough.