I found these pot at a local nursery about six months ago and started using them to mount orchids onto they sell them for vertical succulent gardening.
I find them to be great mount pots, well made, easy to use, the only thing I add is a three wire hanger which I wrap around entire pot so that pot basically is sitting in a wire basket, I tend to over do my hanging wires because I hate when hangers break and plants fall and get damaged.
These pots can be filled with whatever media you use, the front wire area makes it easy to attache orchids to, the only drawback is they can be a little heavy, so use heavy support for hanging.
So far the orchids I have used on these have rooted into pots with no problem, behind wire front of pot is landscape fabric which the orchid roots seem to want to crawl across happily I tend to poke several small holes in the cloth so the the roots also grow into media.
Here is a link, I also have gotten these from big hardware stores.
Penningtonwoodproducts.com