The CV2171 is a noise generating diode for use up to 500 MHz. The filament is tungsten and the prototype was the VX3120. The commercial version is the A2087.
The box anode is mounted horizontally. The filament is a single V.
The bright filament is pure tungsten wire.
The thin glass tube envelope is 17 mm in diameter, and excluding the B7G base pins is 45 mm tall.
