Found them separately,  the ratchet, the push thru,  and the six inch extension.  With the old style ratchet this extension really makes sense.   Plus, I don't remember seeing one before.  The ratchet is Bonaloy, no name or number on the extension.  Are they common elsewhere?

Double male extensions are uncommon, but were available many years ago to go with the push through ratchets.  Walden was one of the companies that had them and I know there were others, but cannot remember their names.

They were still being sold into at least the 50's, possibly the 60's.

Chilly

the double knurled bands scream SK to me.

I'm thinking Hinesdale