HumanScale M7 Monitor Arm Review
 

The upper part is composed entirely of aluminum- even the adjustment knob.
This gives the M7 a quality feel and impressive looks, both of which will
certainly be appreciated in an office/executive type setting. The knob pictured
here is all that is needed to keep the post's gas strut in place once a proper
monitor height has been reached. I was impressed to notice that even the
internal post, which is the end of the gas strut and will not be seen under
normal use, is made of polished aluminum.

Link:
http://www.xyzcomputing.com/index.ph...d=192&Itemid=2