My circular filter kit for each lens size includes a protective UV, a CPL and ND 10 and 6 stop. The K&F kits contain all but the 6 stop. The 6 stop can be ordered separately, though at this time only from the manufacturer's website.

For any given size kit, the K&F Concept magnetic kit costs far far less than would top line individual threaded filters from other manufacturers (Breakthrough Photography, B+W, Hoya HD3, etc.). Yet the optical qualities of these K&F have been tested and are equal to the best. My own experience is that the K&F coatings are also just as effective at repelling water droplets as are my most expensive filters.

Having used K&F Concept magnetic filters in two sizes for a few months I am loving the speed of filter changes and the absence of thread jamming when I stack an ND on a CPL.

My only criticism is the lack of knurling on the front edge of the CPL frame. Magnetic CPL filters do not need or have a two piece construction. The entire filter is rotated in its magnetic attachment, which is fine but remains a two-finger grasping maneuver. To rotate the CPL you'll need to temporarily remove the lens hood. Maybe had K&F added knurling to the from edge a fingertip would suffice, but there is more friction opposing rotation than in a well made two piece threaded CPL. Off course you could attached your old threaded CPL to the lens, screw the open ring magnetic adapter onto the CPL, then add your NDs magnetically. You'd risk jamming the adapter ring to the front threads of your old CPL. I'm not going to do this.

The protective UV is only meant to be attached directly to the lens threads. It is a lens protector. It does not magnetically attach atop the other filters or the open adapter ring. You are give two threaded adapters, one is just an open magnetized frame. The other has the protective glass. The CPL or ND can be clicked onto this protective filter, but not the other way around. My advice is to use the protective UV when facing blowing sand or salt laden ocean mist (and when shooting from a Russian reindeer sleigh where showered by flying feces).