Since I have not yet worked with ND filters, but I do not know what I could complain here.
Overall, I am very satisfied with the glasses from K&F. You get a high-quality, processed filter with a top optical quality and a good scope of delivery (leatherette case).

After many reviews that I looked at on Youtube, I decided on the new K&F filter holder and have not regretted it so far. It is easy to use and makes a very high-quality impression. The use of the CPL filter is a great solution. Lever up, put it in and lever down again, done. Adjusting the wheel is also buttery smooth. In contrast to the first K&F filter holder, the filters, which now have a frame, can now be pushed in very easily. Not too easy and not too heavy either. A clear buy recommendation.

I had never owned a K&F Concept brand filter before and was pleasantly surprised when I first used it in my landscape photography. The reverse graduated ND filters from the popular brands of photographic filters tend to be quite expensive, and this one in particular is less expensive and produces results equal to and even better than those of the most reputable filter brands. It is made of glass, which is an advantage over resin filters because it does not scratch as easily. I really liked the filter cover, which is made of leather with interior protection. In short, I liked this filter very much and I am sure that I will use it very often in my landscape photography.

I wanted a filter holder with these features and an ND filter to start my first steps in long exposure. I chose this brand because I usually like what it offers (and especially for the price it offers, pretty customized)

A sturdy metal filter holder with safety release to put on the adapters and a ND 1000 filter perfect to start taking this kind of photos even in light See in the photos, it comes with a leatherette cover with a soft velvety inside so that the glass and the filter holder do not suffer any damage, although it is presented without cover in the box.

The filter holder would be better if there was a fixing screw for the rotating ring. Otherwise very good.

I bought the graduated filter because it was recommended to me by acquaintances.

Apart from the fact that it is an excellent product, the customer support is simply absolute class I have rarely been treated so reliably and friendly very high praise.

For this price top！！！

Finally found an ND filter which can be installed inside the Smallrig lightweight matte box 2660. I did have to remove the holder frame to make it fit. This can be done by carefully pulling appart the frame sides with the lips. In doing so you can op out the filter while keeping the frame intact. Filter quality seems to be ok and it comes with a very well designed holder with an extraction ribbon which avoids having to touch the surface of the filter when taking it out.

I received the new X-PRO filter set today and have already tested its applicability in the apartment. A judgment on the quality of the filter glasses and the combinability in a shot I still deliver ... The supplied box holds the holder + adapter rings + CPL + ND 8/64/1000. At the drawstring you can pull out the compartments and then very conveniently remove the filters. The plastic filter frames are decently sharp-edged, but not unpleasantly so, and allow you to remove and handle the filter without having to touch the glass. The tabs on the frame also make it very convenient to pull the filters back out of the holder, especially in any order. I have ordered two empty frames in 100 X 150 on the manufacturer's site, which should take my graduated filters after receipt, which I have from another manufacturer. I am curious how well this will work. If it works out, I'll have a complete system for myself, with CPL, three ND filters and two graduated filters (Soft 0.9 and Reverse Soft 0.9). Sliding the filters in and out of the holder requires some force, but is neither awkward nor imprecise. This will then also allow the graduated filter to be aligned well. The handling of the CPL filter with the insertion bracket is great, the turning mechanism is a bit rough, but precise. Screwing the adapter rings onto the lens goes very well, the threads are cleanly made, nothing rubs. Attaching the holder to the adapter ring is also a pleasure and the existing locking screw is very welcome, as the holder can be rotated relatively easily on the ring. The handling of the system has already convinced me, with "only" two slots I can live well for my needs and I look forward to the first use, in the next few days, in the great outdoors and with cold fingers. I have so far worked with round screw filters and waived graduated filters, which I now want to change. I also looked at the system from Rollei (Mark II), which can not keep up with the X-PRO from K+F in handling. Everything very flat and fiddly, offers little surface for holding and joining the parts. Getting the polarizing filter or adapter ring out of the holder again is no fun and almost impossible with cold fingers. K&F has solved this much better. Who wants to use graduated filters is very well served with the X-PRO set, who only needs gray filters, I would advise a magnetic round filter set, whose diameter is well above its largest lens, which is even faster to use, is more compact and should then not darken with several filters in parallel.