I took the name of this neutral density filter to heart and tested it here for actual neutrality of color fidelity and would like to share my results with you.

But first of all, processing and quality:
There really is nothing to complain about here. The filters make a valuable impression and have no processing errors. Everything is top notch here, too. The assembly works without any problems and both filters do not fit too heavy but still firmly on the drone.

Convenience factor:
In fact, that's what appealed to me most about the filters. The thought of only having to change the filters when there are extreme changes in the light situation is tempting!
This was also confirmed in the test. You unpack the drone, give power and set the strength of the filter in Live View without having to think about it beforehand. Also the possibility to stay between two stops is great.

Conclusion:
The idea of ​​variable ND filters is ingenious and if these didn't slightly discolor the captured image, the convenience factor of these filters would be superior to all other filters. These filters are a good choice for all those who find the constant filter change so annoying that they can accept it.