After the first tests I have to say that I'm quite happy but. The ND filter in each bring only a very slight magenta cast in the image of the leaves but rausrechnen without problems in the post. If you want to combine the ND filter, just as I have with a high tempered ND-1000 filter, you should not expect that we obtain reasonable results. Rarely seen such a magenta image and the vignetting is also awful. So always nice to work with a maximum of 2 filters at once. Then everything is wonderful. The color "gradient" filter are partly a little pulled very hard, the course begins with the half of the disc and the disc is at 2/3 to full intensity.
The rings are made of metal, however, the threads are a little dirty, it should in principle not to tighten here because you get otherwise possibly difficulties abzubekommen the adapter ring.
