I bought one of these a few years back. Saw it demo'd somewhere, thought it was cool. Never really used it much, but I needed it again a few days ago and dug it out. Produces a perfectly even clamping pressure on about about any size hose. Then of course I needed instructions on how to use it again.Enjoy.
http://www.youtube.com/watch?v=TrmyeeGfypg
http://www.youtube.com/watch?v=TrmyeeGfypg