I had looked at this and the Peak Design and decided to get this one. It fits my Sony camera, filters, batteries, charger. It has an extra strap that allowed me to bring along my small tripod. Very handy.

This one is better on cloudy days.
I have several polarizing filters from K & F. I think they have made me a better photographer.
It's been snowing lately. I wanted to take photos of the untouched snow. The sun came out and the shine was reflected in the snow. This filter toned down the glare and gave much better shots.
Now, without this filter and my black K&F filter, I never head out to the day.

Snow is too deep for field testing right now. Indoor testing is very good. Easy and straight forward to use controls. Steady signals for each type of metal. Construction is light but sturdy. Will help a lot with my arthritic hands and other joints. Can’t wait for the snow to melt and start using outdoors.

I’ve had this for a few weeks and have used it on a couple of hill walks in the Peak District. The tripod is really light yet sturdy and so make it ideal for strapping onto my backpack. The only issue I’ve had (and it’s minor) is that one of the feet nearly came off - it has unscrewed without my knowledge and might have dropped off had I not noticed. I’ll probably hit it with some Loctite to stop it happening again.

Overall, highly recommended - I really like K&F products and this is another great item

So far I’m highly impressed. I do have a 20L peak design backpack, but I find myself running out of space. Plus that bag is really more like 15L. This holds my A7iii with 35mm attached. My entire drone set up, plus my MacBook 13 and iPad 12.9. And that’s without using the extra storage.

I’ve had this for a few weeks and have used it on a couple of hill walks in the Peak District. The tripod is really light yet sturdy and so make it ideal for strapping onto my backpack. The only issue I’ve had (and it’s minor) is that one of the feet nearly came off - it has unscrewed without my knowledge and might have dropped off had I not noticed. I’ll probably hit it with some Loctite to stop it happening again.
Overall, highly recommended - I really like K&F products and this is another great item

ND filters cause the image to "darken" in order to be able to film at medium exposure rates or larger apertures.
The Osmo Action is of course not a film camera, so I wouldn't say here that NDs are a must - but if you want to film primarily in the SLOG profiles, want to experiment with long exposure (even in the light), try time-lapse recordings or in the snow sun is on the way, he should think about it.

You definitely can't go wrong with the K&F Concept Set. The filters are of incredibly high quality and come in a custom-made case. The case can be closed securely and is flat enough to be stowed in a backpack.
The filters can be changed quickly, which is important because of course you need a different one in the twilight than in the midday sun.

Incidentally, a highlight is the anti-reflective filter, which filters out reflections in the snow or on the water surface, for example. You really get a new perspective with him, which is fun.

got these for my Mini 3 (not the pro), after I accidentally got snow in one of the motors. Fit great, and easy to put on.