I've become a big fan of K&F Concept filters. I have quite a few of their ND/VND filters and a Nano-X series CPL filter that is simply excellent. This is my first Nano-X Pro series filter and while the others are high quality this one is on another level entirely.

The filter has a coated CNC machined brass that attaches to my lens smoothly and comes off without binding. It's slim to minimize any possibility of vignetting yet retains front threads to attach other filters. The edges are knurled and move with a slow liquid feel that helps the filter stay adjusted where you want it. The filter has K&F's Nano-X 36 layer MRC coating that resists glare, fingerprints, etc. and makes the filter easier to clean.

It comes in a slim leather case with magnetic clasp and drawstring that lifts the filter up when you pull it - this is a great feature that helps keep fingerprints off the glass.

As with my other K&F filters this one is extremely neutral without any color cast that I can detect. It has replaced my older B+W CPL filter in my bag and takes the place of my Freewell magnetic ND system when I want to travel light. It's K&F highest-end filter and compared to the competition it's cheaper and better quality making it a fantastic all-around value. Highly recommended.