The ubiquitous red valve. This amplifier pentode was a general workhorse. It was extensively used in radio and radar during WWII. This example was made in America but carries the pre CV VR designation of an RAF receiving valve.
The pins are equi-spaced around the circumference of the pin circle.
The Sylvania name and country of origin.
This valve was made as part of a contract for the UK Air Ministry.
The makers code.
The plain card box that the valve was packed into. The box has black letting on one face that gives the Air Ministry logo, VR91 and the old stores code of 10E/92. This places the date of manufacture to before 1941 when the CV register was introduced and all valves were re-named.
The internal carrier is in two sections. The outer folds as shown to keep the valve away from the ends. The inner is a plain corrugated card sleeve.
The The corrugated card sleeve protects all four sides.
The wide glass tube envelope is 33 mm in diameter, and excluding the B9G base pins is 60 mm tall.
References: Data-sheet & 1040. Type VR91 was first introduced in 1938.