I'm pleased with this monitor stand. There are two parts: an arm with mounting plate and a base. There's a metal key attached to the bottom of the base that you use to attach two screws that link the arm and base; it's also used if you want to adjust the tension for the tilt and vertical motion of the mounting plate. You can either attach the mounting plate to your monitor with four Philips screws or with four thumbscrews. I used the thumbscrews, and they work just fine.
The motion when moving the monitor vertically and when rotating is smooth, and the wide base keeps everything stable. My one nitpick is that the base is a little deeper than I'd like, but I suppose it's that way to ensure stability. All in all, a good purchase.