We use this in the studio to hold up guitar amplifiers to eye level in the control room while the cab is in the live room.
It holds even the heavier amps quite well, although a little bit wobbly, I can put an expensive heavy amp on the stand quite confidently.
The knob system is a bit annoying, you have to turn quite a while before there's any movement possible, but then there's about half a turn left before the knob is completely out.
All in all, quite happy with this, made life in the studio a little easier.