Well it took me a half hour to extract this from the root bed under a tree. It appears to have been copper plated and still is on the inside. The rod at the end is threaded and appears to taper down to a point like a wood screw. I dont see any holes in it like as if it held a filter for something or had tubes connected to it etc. I know it looks like a toilet float, but its only 2 1/2 inches across. Did they make them that small or have you seen them that small? (maybe I better wash my hands, quick) my other thought was a top a lightning rod? a sump pump float? Any ideas? Thanks, Curt O