Be sure this for UWW

Your photographed with an ultra wide-angle (eg 17-40 at VF)? Then necessarily buy these filter holder. There is a second 77mm which is also more favorable. However, this then sitting in front of the lens, which at UWW use leads to strong vignetting. This one lens is screwed, so that the filter holder is mounted on the lens quasi "behind".
The adapter fits well and makes a stable, high-quality impression. Very well matched to the holder.