Update: The filters trip Mavic 3 wide angle lens detection. In fairness, other low cost filters do the same. Now that DJI is allowing "Wide Angle Lens" to work in most modes, it's better, but no Panorama shots when it throws this error. K&F did the right thing and refunded me. If you don't need Panorama, or don't have it detected as the Wide angle its a really nice set of filters. Better than Polar Pro in my opinion.

K&F have a level of quality that's apparent the moment you hold them in your hand. The VND 2-5 Stop, CPL, and Black Diffusion 1/4 (similar in concept to "Mist Edition" Diffusion filters from that OTHER ND Filter company) all rely on rotating glass, and the smooth operation of these shows the build quality and materials right off the bat. If I could nitpick for a second, the lack of indexing marks is less to my liking, but not something I would put too much stress on, since conditions are never identical twice, so what do markings do other than provide a starting point for dialing in. I love the look, the clarity and the quality here. Another nit pick is the case provided. It's soft, semi clear plastic you might buy thumb tacks in, not quality photographic glass. I would say that's not significant in the function of these, but for one point. It's huge. This plastic case will not fit in any of my drone cases. And I have a lot of drone cases. To summarize: some of the nicest filters in the business. Case is terrible.