I hesitated before buying this set of filters, and finally I did. The filters are made of plastic, of sufficient quality for use year we can have. The filter holder is solid, but still afraid of damaging it by fixing it on the ring. Speaking of rings, there is everything, from the smallest to the largest. That's a plus. Be careful not to over abuse, not to superimpose the filter this gives a fairly strong magenta coloration. The black and white transition is the most reliable solution in this case. One filter for the sky is enough to give it more depth and limit its exposure. For the price, frankly, it's nice.
Edit - On larger sizes it seems the color is less important.