This exhibit is an Electrad Diode fitted into a base also made by Electrad. The silvered glass shows that this valve has been gettered and is thus a hard vacuum valve..
Electrad Corporation of America made midget valves in 1923 and were based in New York
We also have the un-gettered soft version here.
The original box.
Thanks to Joe Gruber for sending the images.
The thin glass tube envelope is 19 mm in diameter and, including the base pins, is 83 mm tall.
Reference: Joe Gruber.
Updated December01, 2020.