I've used it a few times with an exposure calculator and it was pretty accurate.

Came really well packaged and a great value. Filter seems good, no noticeable hues, adapter rings for most size lenses and the metal holder seem durable

To be honest I was really hesitant to purchase this, however the price intrigued me enough to give it a try. I have to say this ND Filter is right up there with the best. It comes nicely presented and the case to store it in is great. There have NOT been any weird coloration in. The glass is high quality and easy to clean. Honestly I love this ND Filter.

Really good filters. For the money and got quality

First time using an ND filter and I’m really pleased with the photo I took. The quality is really good. Thank you!

Great product for the price.

Very high quality-price ratio. 100% recommendable.

Nice finish with a excellent thumb lock. All metal parts that are machined to fit perfectly. Very nice product with first class glass. Made in England.

I got this for the filter holder and adapters. They work great!
Mad the filter that came with it is pretty decent.

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.