These are so easy to use and the quality is fantastic - both the build quality and the picture quality. I can't see any colour cast whatsoever from both the CPL & ND filter. I think you would really need to pixel peep to see any sharpness difference, and even then I'm not sure there is.
Being able to attach the filters to both the UV filter and filter ring is really clever - I keep the UV on my 24-70 F4 and the filter thread ring on 16-35 F4 so it makes it even faster to clip on the filters no matter what lens I use.
Since the ND isn't variable, there's no dark X. And no vignetting at 16mm, unlike when I use my square filter set.

The downsides that I see at the moment:
- You can't replace the filter thread on its own, so if you break or lose it, you have to buy a new set.

The filters appear to work well in testing. I would not trust them to remain on the camera when in the field. The magnetic mount is not strong enough. Fine for tripod use and then take the filters off and put them back in their case.

I purchased this K&F Concept 67mm Magnetic Lens Filter Kit
for my Tamron 28-75 f2.8. These filters work great and fit on my new camera.quality looks good.
It was a great choice!.... It allows me to capture long exposure water shots on bright, sunny days. It's not a variable and it's too dark for those dark dreary, overcast days. You'll want a different filter for that. The filter is well made and easy to thread onto my lenses. It also comes with a nice case to store and carry. The images come out clear and sharp with no vignetting, like you might get with some filters. Great value, definitely worth the money. I am happy with this purchase.

Very easy to set up and use. The magnetic rings fit very well. Picture quality is excellent for the price, although the polarizer and ND filters have a slight hint of a tint on the warm side (which can be very easily adjusted post shoot).
One item this package should add is a magnetic lens cap to provide better protection to the filters during transit.

This is a solution for one of my pet peeves, taking filters off and on in the field. I always carry a CPL filter with me when doing a shoot, but it is difficult to take them off and on in the back of a Range Rover on the move. This one is protecting my Olympus 300mm f4.0 lens (UV) and allows me to quickly switch to the CPL when I need it. I ordered another set for my 72mm lenses. Great packaging, good carrying case and I'll be able to cover all my field lenses with the two sets. Extremely impressed with the ease of rotating the CPL filter. My lens cap stays on with no problem and can be either on the CPL or the bare magnetic mount. The magnet is very strong, the filters stay where you want them until you want them off.

If you are looking for good quality filters that don't negatively affect your image and are very easy to carry and use, I would definitely buy magnetic ones. Carrying the square ones is sometimes a nuisance and I find the threaded ones much more uncomfortable, apart from the risk of them falling off, I'm a bit handy and it has already happened to me several times with the threaded ones. With these so far no problem and I'm very happy.

I shoot in various elements and destinations where lighting is different and filters are needed for optimal results. I have been using the traditional screw on filters but I find it time consuming especially how it needs to be aligned perfectly on your lens, taking up to a few minutes for each one when I could miss the opportunity of my shot. I find this K&F filter set to be a great choice for me. I am no professional by any means and take photos for fun with my Nikon d850 and these filters have worked great for me. The magnetic adapter ring is easy to screw on the lens and the lenses stick to it well. These lenses work great in the rain and are not only waterproof but the water beads off of them. I have not had any issue of fogging between the lens and filter.
The come packaged nice in a hard case, each in its own slot. I find this to be a great value for all of the different lenses offered in this set and I am extremely happy with them.

This is a kit,the combinations to use CPL and ND1000 can be:
-Adapter+CPL, Adapter+ND1000 or Adapter + CPL + ND1000.
-UV Filter + CPL, UV Filter + ND1000, UV Filter + CPL + ND1000, UV Filter+CPL+ND1000

Comes in a padded case with a reverse zip to prevent any water from getting inside in case of rain. It can be clipped on the belt or anywhere else for comfortable use or transport.

As far as image quality is concerned I have few complaints, I haven't noticed any loss of sharpness or colour cast. I have been able to use both the UV+CPL+ND1000 up to 12mm on my APSC camera without vignetting.

All 3 filters for me are very useful. The stand-alone ring however, I'm wasn't sure how much I'll actually use it but surprisingly I just leave it on my lens unless it's pretty bad weather, which in turn I use the UV filter as a protective layer for the glass.The CPL filter works wonders and the ND filter is great for long exposer shots. the combination with the magnetic touch make this absolutely flawless. would recommend

I really like the convenience of this magnetic filter system. You only need to thread on the base ring and magnets do the rest. Makes it less likely to damage the threads of your lens if you don't have to keep putting on and removing a filter on every time you need to use it. I am using this with a 24-105mm full-frame lens and the base ring works with the lens cap and the hood although you probably need to remove the hood to snap on the filter because otherwise your fingers get in the way.
Each of the filters themselves are quite a bit heavier than the screw on K&F versions, probably because they need to make the filter ring out of a magnetic steel instead of aluminum. Whatever the reason, they feel a lot more premium than the regular K&F version.
In terms of performance, its a bit of a mixed bag. I don't have tremendous experience using CPL and ND filters (this is my first set) so I don't know what's considered good performance at a given price range.

Moving on, the CPL filter (photos looking out the window) has similar vignette to the ND filter at 24mm but appears to cut down quite a bit of reflections in my windows. Not much for me to point our here, it seems to do the job.
The set does come with a UV filter but I do not intend to use it unless I am in a rainy/dusty environment where my lens needs a bit more protection so I haven't tested it out yet.
For both the ND and the CPL filter, I did not detect any noticeable decrease in sharpness caused by using the filters.
I think the performance of these filters is acceptable. I am a little disappointed with the vignette but I have heard of much more expensive filters having similar issues so I don't want to be too hard on this set. All in all, for someone like me who does this for fun, I think its a great system to learn the basics until I can justify the move to something more premium.