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.

As a beginner to experimenting with filters, it comes with all I need to start with, at an affordable price given such quality and design.

I bought the rectangular filter set directly from K&F. Since I have worked with screw filters in the past and had the problem with vignetting when screwing several filters on top of each other, I have wanted to buy a rectangular filter set for a long time. Since the sets from NISI, Haida and other well-known manufacturers are very, very expensive, as a hobby photographer I was looking for a cheaper alternative. When I saw several reviews on YouTube, I decided on the K&F set, which is half the price of Haida and CO. I have absolutely no regrets about my decision. The filter holder is very valuable and well thought out. I particularly like how the polarizing filter is attached to the holder and how it can be adjusted using the small wheel. The filters themselves are made of optical glass and show no color cast and are also well coated. Another positive aspect is that the filters have a plastic frame with a tab. This allows the filters to be inserted and removed without annoying fingerprints. A bag is included to store and transport the holder and the filters in it. Also included are various adapter rings for different filter thread diameters. As a landscape hobby photographer, I no longer want to do without the advantages over screw-on filters. I give a clear purchase recommendation for amateur photographers and professionals too! I wasn't expecting such excellent quality for this price. It's amazing what K&F delivers here.

Mejora el sistema anterior asegurando los filtros al objetivo.

Good quality. Relatively easy to use. A bit pricey.

Super leicht zu handhaben. Kommt in einer mitgelieferten Tasche. Qualität ist Mega. Habe den Kauf nicht bereut. Es macht Spass und die Bilder sind aus der Kamera schon sehr schön.

Mit besten Grüßen

Works great on my Nikon Z6 16-30

Very nice kit with CPL, adapter rings, and ND filters. Came nicely packaged in a leatherette case. Overall build quality is excellent.

Produit parfait qui s'adapte vraiment bien à tous les objectifs ! Ça permet d'avoir qu'un seul support. Très belle qualité avec la pochette de rangement.
J'avais perdu une visse et le SAV a été très réactif et ils m'ont renvoyé un lot de visses.

Ist alles so wie beschrieben.