Adapter ring: I have just bought this package as it is much cheaper, even 12, xx to pay for a set of adapter rings as per original adapter ring 12th Although these are not originals these excellent fit to the filter thread of my lenses. The material is made of metal. The original filter holder of Cokin fits very well to the adapter rings.
Filter holder: I can not say anything because in other reviews a couple of times it was mentioned that this filter would ring to fit too well. And I use the original from Cokin. The holder of the set is still packed.