After someone was singing its praises on this site in early December, I ordered one. There must have been a terrific rush on them, because it ended up being backordered and I didn't receive it until well into February. I haven't had an opportunity to use it yet, but am looking foward to it in a few weeks. I was planning on making one, according to someone's instructions from long ago, but by the time I hunted up 2x4 pieces and tennis balls, bought dowels and heavy duty magnets, I figured I'd just a soon buy it and it wouldn't cost much more. Plus, it would be collapseable, which might come in handy.
It looks like those guys are telescoping so that the height of the ball can be set. Now for the question, how to get them to line up (up and down) like shown in the picture?