I have both the GoPro 11 and the DJI Osmo Action 4 cameras, as well as the DJI Mini 3 Pro drone. I use ND filters for all of them and the drone ones also come from K&F Concept. I'm very happy with them.

The really cool thing here is that these are both ND and PL filters. Why? Because if you have them as separate filters, there's no way to use them together.
If you're looking to get these, you're probably aware what ND/PL filters are. But there's a small chance you may just be exploring various available accessories for your new camera. So ND filters will help in that really sunny weather, where your camera sensor gets too much light and the picture looks overexposed. It blocks an amount of light depending on which filter you use. The result is better contrast and richer colors. The PL filter further enhances it by removing unnecessary glare. Now glare can be found in more than just the surface of water. It can be a glass or metal object, snow or even…leaves. Just look at the video.
The filters are really well made. The glass looks and feels strong and solid, the threads fit perfectly and the whole thing looks really professional. The PL filter can be regulated by twisting the ring.
I like the storage box. It's hard plastic with some nice foam cuttings. The filters are easy to take out and well protected from damage.
The weather wasn't good enough when I filmed the video, but at least I had some sunshine. Summer's gone - what can you do? The difference the PL filter was making can be clearly observed though.

I've seen loads of videos where people don't utilize these filters enough. It's a quick operation to swap them (much quicker than on the drone!), so I'll have them with me everywhere. The price at £43 for 4 ND/PL filters of this quality is really good. Definitely happy to recommend.

Thank you for reading my review. I hope you found it helpful.