This socket has the tell-tale Truth vertical line knurling, the size and U.S.A. stamped into the side.
This is an early version of the Blackhawk Lock On sockets. The patent pending is believed to refer to the patent for the lock on technology. The patent was filed in August of 1929 and awarded in February of 1934.
One thing to notice is the difference in the broach between the Circle H, and the BE, which are both made by New Britain during the same timeframe.