Google "TS742", that's the one I use. I can't add the brand, because the brand is basically the name of the shop (on one version anyway). It does seem to be used by other brand names as well.
The only thing I would say about it though, is that the bigger the monitor, the more it restricts the horizontal angle they can be placed at. In my opinion, the arms needed to be slightly longer, to allow more of an inward tilt. I use mine on my NEC 20WGX2 Pros, and it's fine. I did try it with a pair of 24" (on one of my numerous failed attempts to upgrade my monitors), but they wouldn't turn inwards quite enough for me. I think if I sat further back, it would be okay with the 24s, but my eyesight isn't good enough to do that.