Hello Annie,
as we are custom design and build, we made it ourselves. The flanges are available commercially or you can get them fabricated; they are fixed with a set screw to a ground solid stainless steel rod. The flanges are fixed to each lazy susan shelf with fasteners. The shelves are constructed from baltic birch plywood and edged with a paduak and maple lip. I would be happy to organize a custom one for you if you wish, just send me a note; or if you require more details, please ask.
Regards,
David Stepan

Lazy Shoesen