This is an adaptor to use a Balscope as a telephoto lens.
I think all parts are there. Original corrugated cardboard box
says "Tel-Master" etc and instruction sheet as well.
I got at an auction a while back as I thought maybe
I could use it as a camera piggyback mount, but it has sat in the closet.
$20 and buyer to pay shipping as there is some weight with
steel square rods and the like.