I wanted a filter holder with these characteristics 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, pretty much adapted for the price it offers) A sturdy metal filter holder with a safety trigger to place on the adapters and an ND 1000 filter that works perfectly is to start with this type of photo even in the light, see the photos, it comes with a leatherette cover with a soft velvety inside so that the glass and the filter holder are not damaged, even though it is presented in the box without a cover.

Had screw-on filters for years. Of course they work, but a plug-in filter is really practical, especially for landscape photography. I first bought the filter plug-in system from K&F (Nano x per row). Now have some filters. Filter and plug-in system highly recommended. I'm really excited. Goes fast, good quality and you can also leave filters on if you want to go a few steps further. I also like the frame around the filter. That way, greasy fingers don't get on the filter so quickly. Nothing wobbles. There is also a stylish filter bag.

The gray filter comes in a sturdy protective cover and fits exactly into my rectangular filter holder. The optical properties do not reveal any defects. A satisfied customer thanks you.

Great kit, provides all the basics to cover most situations all neatly packed into nice filter holder, great results from my first few outings. Five out of five stars.

I have long played with the idea of buying a graduated filter, but the prices of Nisi, Haida, etc. around 150 euros have always deterred me. Then I came across the filters of K&F, since the filter was in a Preislich favorable frame I ordered them.

For a while I had been hesitating between several brands to choose a filter holder for ND and GND filters. I took advantage of a flash sale to buy this kit. I am not disappointed.
The set seems sturdy and easy to store.
The case, quite pretty, has 5 compartments, 3 of which, for square ND filters, are raised via a ribbon. On the back of the case, there is a belt loop and a belt loop. I would have liked a slightly more spacious compartment to house the adapter rings with the CPL filter when it is removed.
The assembly (or disassembly) of the elements is well explained in instructions in several languages, including French.

Main positive points:
No dominant color, nor loss of sharpness on the first tests carried out.
The plastic frame with its tabs to handle ND filters.
The system for installing the PLC filter on the filter holder.
the knurled button for mounting the adapter ring and for rotating blocking the filter holder.
The very accessible wheel to control the polarizing filter.
The sturdy holding of the square filter on the filter holder.
The robustness of the metal filter holder.

If you have to find slightly negative points: Keeping
the square filter a little too sturdy in the filter holder.
The click too loud to lock the CPL filter in the filter holder.
No pouch to independently protect the CPL filter in the case.
No protective cover for the CPL when the set is installed on the lens.

I use it for long exposure photography.

The quality of the build of the rings / holders is excellent. The filters themselves come in leather-like pouches. The image quality of pictures taken using these is really good.

I've used the filter several times and it works great plus the mount works great and have already used other filters with it...

The adapter rings allow us to place the filter holder on any lens, as we have a large number of different diameters. They are made of black metal and well finished. With labeling on each ring with the corresponding diameter.The filter holder is metallic with the part where the filters go from a kind of hard plastic. Two 100x100 filters fit and 100x150mm gradients without any problems. The attachment system to the adapter ring is via a very manageable metal tab.In several tests I did under different lighting conditions, I did not notice the entry of residual light through the space between the filter and the filter holder. The photos have a slight magenta tint that is very easy to correct when editing, but it is not at all overdone. I am very pleased and enjoy it very much. I recommend it!