This is a very versatile system and a quality product. The tabbed filters slide in and out of the holder without difficulty. So far, no light leaks. I love the ability to get frames for my additional filters, 100X100 and 150X100. It keeps fingerprints off the filter.The company is based out of Hong Kong. I would have liked to get additional adapter rings, but the company does not sell them separately, or so it seems. I've contacted them via their web site/email address and keep getting ads for their backpack. I was referred to get magnetic adapter rings which are not for this system. It appears if you want to get adapters you need to buy the filter holder and adapter rings.This is definitely a product to purchase. I look forward to shooting pictures with it. It would be nice to have a wide angle lens shade, but then, you can't always get what you want.

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.

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.

Very high quality ND1000 K&F Concept square filter set consisting of glass filter, filter holder and lens adapters for the filter holder.

The package is divided into 3 parts:
1. a bag with metal adapter rings for lenses with different diameters.
2. a box with the filter and its leather carrying case.
3. a box with the filter holder.

The adapter rings allow us to put the filter holder on any lens, since we have a large number of different diameters. They are made of black metal and well made. With inscription on each ring of the corresponding diameter.

It is a square filter ND1000 100x100 mm and 2 mm thick. It allows us to remove 10 light levels to make long exposures in daylight perfect. In the example photo I posted, it is taken at noon at 30 ". I love the play that can be taken from this filter.

The filter comes in a leather case and is covered with tissue paper. The case is sturdy enough to protect it properly.
The glass is not easily marked by fingers and does not attract dust.

The filter holder is metallic, with the part where the filters rest being made of some kind of very hard plastic. They easily fit two 100x100 filters

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.

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.

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.

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 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.