For a while I had been hesitating between several brands to choose a filter holder for ND and GND filters. I took advantage of a flash sale to buy this kit. I am not disappointed.
The set seems sturdy and easy to store.
The case, quite pretty, has 5 compartments, 3 of which, for square ND filters, are raised via a ribbon. On the back of the case, there is a belt loop and a belt loop. I would have liked a slightly more spacious compartment to house the adapter rings with the CPL filter when it is removed.
The assembly (or disassembly) of the elements is well explained in instructions in several languages, including French.

Main positive points:
No dominant color, nor loss of sharpness on the first tests carried out.
The plastic frame with its tabs to handle ND filters.
The system for installing the PLC filter on the filter holder.
the knurled button for mounting the adapter ring and for rotating blocking the filter holder.
The very accessible wheel to control the polarizing filter.
The sturdy holding of the square filter on the filter holder.
The robustness of the metal filter holder.

If you have to find slightly negative points: Keeping
the square filter a little too sturdy in the filter holder.
The click too loud to lock the CPL filter in the filter holder.
No pouch to independently protect the CPL filter in the case.
No protective cover for the CPL when the set is installed on the lens.