We never were told exactly what these cylinders were going to be used for. What we were told is that they were going to contain some form of exotic gas that has some metaphysical purpose. We gold plated many of these tubes and the valves at the end. The tube is made of a 300 series stainless steel, the valve was stainless and chrome plated brass. There were two sizes. The longer cylinder, shown here, is about 10 inches long there were also some that were about 6 inches long.