For a while I had hesitated between several brands to choose a filter holder for ND and GND filters. I used a flash sale to purchase this kit. I'm not disappointed.
The set is sturdy and easy to store.
The rather pretty body has 5 compartments, 3 of which are raised via a ribbon for square ND filters. There is a belt loop and a belt loop on the back of the case. I would have liked a slightly roomier compartment to house the adapter rings with the CPL filter when that is removed.
The assembly (or disassembly) of the elements is well explained with instructions in several languages, including French.

Main positive points:
No dominant color, no loss of sharpness in the first tests performed.
The plastic frame with its tabs for handling ND filters.
The system for installing the SPS filter on the filter holder.
the knurled knob for mounting the adapter ring and rotating locks the filter holder.
The easily accessible wheel for controlling the polarizing filter.
The stable hold of the square filter on the filter holder.
The robustness of the metal filter holder.

If you must find some negative points: hold
the square filter in the filter holder a little too tightly.
The click is too loud to lock the CPL filter in the filter holder.
No bag to independently protect the CPL filter in the housing.
No protective cover for the CPL when the set is installed on the lens.