This exhibit is the Moorhead Special transmitting valve that was made for the US market. The internal gettering gives the glass a gold appearance.
Thanks to Joe Gruber for sending the images.
The balloon envelope is mm in diameter and, excluding the base pins, is mm tall.
Reference: Joe Gruber. Type Moorhead-Special was first introduced in 1917.
Updated June 13, 2020. shape:balloon construction:pinch type:triode age:pre.1920 base:uv pin:1.g1 pin:2.f pin:3.f pin:4.a