I've broken down my review for you and them into reason for purchase, first impression, product test, suggestions for improvement, tips and conclusion. I hope this helps with clarity.

I received the product free of charge as a Vine product tester, but this has no effect on my review. I also only test things that I can usefully use myself and integrate into my everyday life.

Reason for purchase:
I ordered this filter for 2 reasons. The first reason is that if I only want to travel with light luggage, I don't want to bring my entire plug-in filter system with me. The second is that I can use it well in videography, where I usually film according to the 180 degree rule. This means that in order to obtain a cinematic video image with a certain amount of motion blur in the individual frame, you film with a shutter speed of 1/fps x 2, for example, I film at 50fps, so I need an exposure time of 1/100s, which is not possible without an ND filter, especially in the wide angle range when the sun is shining.

First impression:
The packaging looks very classy, but she is also welcome to do that, given the price that is called for the filter. The filter is in an equally pretty and high-quality filter bag, which I have never seen in this form with round filters before. With the tab on the side, you can lift the filter to prevent accidental contact with the glass when removed. The closure of the bag is magnetic. A nice gimmick is that the cardboard packaging of the filter can be transformed into a small picture frame.

Product test:
The filter is a dream to the touch, heavy (91g) and easy to grip, I also really like the contrasting adjustment aids. These can also be removed if you want to continue using a lens hood. This requires a small microtorx, e.g. from a precision engineering kit. When the filter is adjusted, it is buttery smooth across all stages.

In the test, the filter shows no weaknesses. As a result, I could not detect any color cast and there was no X-Cross effect. The promised effect of up to 5 aperture levels is maintained. Technically perfect and that is the most important aspect of an ND filter.

Suggestions for improvement:
1. The sustainability aspect, as taken up when using cardboard as a picture frame, could also be reflected in the filter bag by avoiding the use of animal products (leather).
2. An 82mm variant would be desirable and recommended, then the filter could also be used on (m) a 24-70mm/2.8, for example.

Tips:
It is always advisable to buy such a filter in the largest possible diameter so that you can adapt it to as many lenses as possible in your own fleet using step-down rings. Of course, this also eliminates the option of continuing to use a sun visor.

Conclusion:
Technically perfect filter in the upmarket price segment.

I hope my review was helpful in your decision making