2kg boxes have thus attached to plasterboard: it keeps!
It also looks very inconspicuous from (although they are in any case largely hidden behind the boxes) even when viewed from the side of it. What is not on the pictures: the holes for mounting on wall / box can be covered by caps attached, provided that no screws are used with a very large head. However, the caps sit so loose that I had to save it with adhesive.
Despite stability of the supports they clearly been on in my 2kg boxes by: The arm pieces, namely the joint between the arms and the wall / boxes mounting plates remain rigid, but the pivot joints between the arm and plate consist of only one about a centimeter thick pin of the arm rotatably attached and is secured by a screw: by 2kg weight created quite a visible gap between the poor and drive and you have a bad feeling to be able to tear off the pin by strong movements.
Since I am but the boxes rarely touch, that's all right: for frequent mechanical load (such dusting of boxing, realignment, etc.) are the holders in excess of 1.5 kg load DEFINITELY NOT SUITABLE!
As others have noted, the Assembly is to deal with quite cumbersome and difficult alone, because you only the two arms with the plates each to box and wall screws (simple) and then the box must uphold so that both arms come together in joint , now with the other hand with the loose (!) nut and bolt must fix the joint ... and all this up on the wall!
A snap mechanism would have been very helpful here! One could of course stick to the mother at least - I have the arms rotate so that the mother initially shows up and so can not fall out, then purely turned the screw and then all rotated and aligned the way I wanted the Boxne before I all screws have tightened: it went pretty hard on the arms!
But now everything depends and I am very satisfied!
Conclusion: you need very patient, reasonably technically gifted people for assembly, but then, with speakers up to 2kg per mount his pleasure (!)!