The biggest maker of these "was" Harry Owens. When he passed everything was sold to a guy in Anchorage Alaska, and be damned if i put my finger on his addy right now!!!

Anyway, do a search on subchambers, or maybe Harry Owens and see if you can get it.

I sold a lot of these in the past, i even worked with Harry to build some spl. made ones. I liked Harry, he was always great to work with. (ay least for me)

I still have quite a few of them around and they can be a lot of fun, even though some models are quite slow to use.

Drilling Man