>>2935141 (OP)
I have exactly the model in your picture.
It's a complete shit. The ball does not fasten securely the upper part (which can be exchanged from vice to pipe holder). Whole thing wobbles. It's a worthless cheap crap.
It's so shitty that even the threads are not trapezoidal.
My angle grinder handlebars use a standard M8 thread to fasten them. When I needed to hold in place my angle grinder, I took a M8 bolt, used one nut to secure the bolt in the hole for the handle, added another, long nut (coupling nut) that can just be held tight by a normal vice.
There are also dedicated stands for angle grinders (that also use the holes for handlebar to fasten the angle grinder, plus some extra rods that just stabilise the housing to prevent rotations thereof). I also got one of those, it's nice for clean & precise cutting, and you can also use it to hold the angle grinder in place, alas tool can be secured only vertically in such contraption.
I used the vice method for I wanted to secure a 115mm angle grinder, and I got the stand for a 230mm one.