The positive comments on the Manfrotto umbrella holder, I would add one point. With competitive products, I've always been pretty annoyed that only the top half of the screen reflector is illuminated by the flash (Metz 58AF-1). This resulted from the fact that the hole was introduced for the umbrella pole exactly at right angles. Because flash sits above the umbrella pole, the flash head is about 15cm above the screen center.
When this Manfrotto umbrella holder the hole is a few degrees (15?) Drilled diagonally. In order that the flash lights up perfectly in the center of the screen. Also in the transmitted light mode / softbox this becomes noticeable by a more even light distribution.
