The NS2 neon voltage stabiliser was made for the UK Navy. This exhibit has lost most of the lettering. It reads Admiralty Pattern, 5459 but the 9 looks like an 8. Below are the remains of the Type code NS2. The serial number has been obliterated. After 1941 with the advent of the Common Valve register the NS2 was re-designated CV1199. This exhibit makes no mention of the CV number and is thus earlier than 1941.
There are only two leads passing through the pinch. The internal view shows a mica base and three concentric cylinders. On test the valve stabilises at 102 Volts at 50 mA - within the tolerance of the specification. This is a stabilisation tube and not a voltage reference. Other versions of the NS2 have ceramic insulation sealing the working area.
The pinch and internal connections.
The wide glass tube envelope is 51 mm in diameter, and excluding the B4 base pins is 140 mm tall.
Reference: Datasheet. Type NS2 was first introduced in 1940.