Blenko Glass Bottle Art Tree

Hillery,
Can you tell me what they used to make the bottle tree in Blenko yard?
I have many bottles and stoppers but need to know how they are staying on the tree.  I want to use some of my Mom's milky and sick  older pieces to make this as a surprise for her. 
Alex S.

Alex,   We'll send a note to Dean Six  and ask where they purchased the metal hangers and also the rubber inserts ( see photo below).
Good luck with your recreation of the Blenko Glass Bottle Tree.   HJH