I've known K&F for a while now and have one or the other product from them (UV filter and camera backpack). Here, the brand was always technically good for me and was more in the middle price segment.
But now they want to know and are moving into the high-class sector.

An ND filter reduces incoming light. With this variable from ND2 to ND32. This makes it ideal for long exposures and to “artificially” extend them. Especially when moving processes such as rivers, waterfalls, road traffic and others, beautiful soft courses can be achieved.

The filter comes beautifully packaged and is really fun to unpack. If you love unboxing, this is the place for you.
The filter comes in a fabric/leather bag. Very nice in itself, but in my opinion a filter fits richer in the well-known plastic cases.
The inside of the packaging can be converted into a “picture frame”. Jokes idea but I think there are better ones.

But let's get to the filter itself. Here I have to say that the performance matches the price. Clean processing, both on the filter thread, ring and glass.
The filter is easy and easy to unscrew and remove again, which is no comparison to cheap filters.
The glass is of the best quality and its optical performance is indistinguishable from other ND filters from well-known competitors.
This gives you uniform darkening over the entire image and levels without loss of quality or any color strokes.

In summary, this is a very good filter in terms of its quality and optical performance. It has weak points in the somewhat loose fixation in the storage bag.

What I personally miss is rest steps so you know where you are right now.
I'm a bit divided in two when it comes to the price. The quality of the filter corresponds to the price, but I don't know whether I would buy it. Because for the price, you can buy a rectangular filter with suspension and corresponding filter.
I also find the range from ND2 to ND32 a bit unfavorable as it is quite little. But that is my personal opinion and, of course, it always depends on the user.