I just opened up my latest Drs. Foster and Smith catalogue and the hanging gym that I have for my guys is now being offered through them (for $16.99). Some have seen pics of my gym and ask where I got it from, and I ordered it from a store out in CA awhile ago (found it through something else in a magazine).
But it's similar to the Hoopball that many of you have made for your larger birds, and this is a great small version for the tiny guys.
Both Jerry and Lulu love this gym:
