These are some of the vibration dampers that I have followed me home over the years. David Dahle sent me this informative link http://en.wikipedia.org/wiki/Stockbridge_damper which explained many aspects of their use and design. The largest one in the picture is almost 27 inch, was not specifically mentioned in that article. It is also the only one made from aluminum. I suspect that it is a finely tuned piece of equipment considering the amount of grinding and polishing done to the aluminum ends. If anyone has info on it's use and design, I'd be pleased to add it here.