Support arms are stable - stay in position as you set up. They doesn't twist down when you unhang guitar. However you have carefully hang and unhang guitar not to widen brackets. Or you have to correct them.
The brackets are covered with not cork, but rubber. You can find that in data sheet on manufacturer?s website [LINK] . It hardly resembles cork. It?s texture is very fine and it is very dark, not as on the picture above. Nevertheless it looks nice.
I got about 8 of these in 2011 [its 2016 now] and they are still going strong. I was sick and tired of guitars lying around my house so i opted to put them out of the way and on the wall with a cork guitar holder. Great for the price and more space for me. J.