Here is another alternative on the cheap.
http://www.tensimount.com/ordering.htm
I actually have a pair of these and like them alot. Had them for 2 years or so, still going strong with several hundred shows under their belt.
I was looking at those as well, thought they looked a little fragile.
They metal or plastic?
And, about how far apart are the two rings?
Thanks
I'm not sure on the distance. I'm away from home and can't check. FWIW, I never rant those Avensons in them as I ran them in the rubber clips (that I couldn't find to ship to you) that came with them.
The Tenismounts are plastic, but are sturdy. They have been to B'roo twice, to all sorts of crazy taping enviroments, squashed down in my bag, dropped, the whole shebang and they work just fine. I highly recommend them as a cheap alternative mount. I'm sure you could contact the company by email or phone and ask the dimensions/distance between the two rings.