Yeah that's the one. It does what a $75.oo lens collar does for $800.oo 
I know some lenses don't have collars, but really! When I got the first catalog showing this device just a year or so ago, I remember laughing and laughing for minutes on end. A serious case of finding an elaborate way to solve a problem that no one really has.
they are so defensive about it's design now they edited the website to actually tell you exactly the one individual that seemed to have this issue!
to Melvin Sokolsky;
You lazy man!
