Even after significant adjustment on the Allen screws and packing with card and rubber the ball joints are way to loose and the screens just flop all over the place. The swing arms aren’t particularly good either

Have had a few of these now Come with a bunch of different screws to fit most sized VESA set ups They are sturdy and once set up, they lock up well without being slightly loose and moving round

Even with extreme tightening on the 3 allen screws around the ball joints at the ends of the arms, neither can hold a 4kg monitor vertically upright. They tip forward, so as to make it unusable. I will be returning it. Maybe just this one is faulty, based on the other 5 star ratings that have been provided.

Product is better quality than expected, a great deal. Supports my two monitors easily.