The 6SA7GT is an interesting exhibit as it has an American type designation but is made by Mullard. As a heptode it was designed as a self oscillating mixer for radio reception.
The wide glass tube envelope is 28 mm in diameter and, excluding the IO base pins, is 68 mm tall.
References: Datasheet & 1043. Type 6SA7GT was first introduced in 1940.
Absolute Maximum Operating Conditions¶
Updated January 31, 2013. shape:wide.glass.tube construction:pinch type:heptode age:1940.1950 base:io heater:6.3v pins:8 pin:1.m pin:2.h pin:3.a pin:4.g2.g4 pin:5.g1 pin:6.k.g5 pin:7.h pin:8.g3