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

An ND filter reduces incoming light. In the case of this ND1000 around 10 stops. This makes it ideal for long exposures and to “artificially” extend them. Especially when it comes to moving processes such as rivers, waterfalls, road traffic and others, beautifully smooth flows can be achieved.

The filter comes beautifully packaged and is really fun to unpack. Anyone who loves unboxing will enjoy this to the fullest.
The filter comes in a fabric/leather bag. Very nice in itself, but in my opinion, a filter is richer in the well-known plastic cases.
The inside of the packaging can be converted into a “picture frame”. Joke idea but I think there are nicer ones.

But let's get to the filter itself. Here I also have to say again that the performance matches the price and is absolutely justified.
Clean workmanship, both on the filter thread and on the glass.
The filter is easy and easy to turn on and remove again.
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 without loss of quality or any color casts.

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, which costs half a star.
However, we are still rounded up to a full 5 stars and a buy recommendation.