Help Identifying Vintage Socket Set

[hosspapa]

Came across this socket set the other day but haven't been able to identify it.

Red Metal case - lid slides on/off -- but no marks remain.
Inside all the tools have no manufacturer mark. The only mark is the size inside a circle and the words PAT PEND.

I've attached a few pictures. Any info would be greatly appreciated.

Thank you.

 

[MR.X]

That "circle" is the Hinsdale "H".

 

[hosspapa]

Thank you!