First the good. It's a well machined and properly threaded magnetic ring with a multi-layered optically clear polarizing filter. The filter is easy to rotate to find optimal polarization. Results are as expected when images are taken under the right conditions. Darker, richer blue skies, especially in typical landscape shots. The magnetic ring allows for quick swapping with other filters or stacking multiple filters. My issue is that my standard lens cap for a Sony 24-105 F4 G OSS lens won't work on the lens that's in the magnetic ring or the magnetic ring itself. I get it. It's a kit that requires a K&F cap. That's the exact same issue I had when reviewing a previous combo lens from K&F. Looking for the lens cap that goes with the CPL on Amazon? Extra, but available. This was the case almost a year ago when I reviewed a similar combo. I rarely use a lens out in the field without a cover available. Multiple protective cases? Another inconvenience. Sorry. Minus 2 stars for not fixing this issue. There's little point in having a two-piece kit that only includes a magnetic ring and a filter, especially if this is your first K&F kit. Bottom line? Be sure to order the kit with a lens cap if it's important to you. 5/5 for optical clarity and lens functionality. No lens cap? 3/5.