bought this one coas i needed a somewhat cheap boom arm for my AT2020 mic, and it works great, the arm keeps still and its somewhat easy to adjust it to your needs,
i had some problems getting the part where you fasten it to the table to stay in place, so i ended up drilling two holes from the top of the "plate" into the table, and then screw it in :D. now it wont move eaven if there was an earthquake :;D