The XN13-FA is a cold cathode indicator tube. The gas filling is neon and the red coating on the glass enhances contrast.
These indicators were used in counters that were used for ballistic speed measurements.
Thanks to Eric Luiijf (Waalsdorp Museum) for sending the image and information.
The thin glass tube envelope is 15.5 mm in diameter and, excluding the base wires, is 46 mm tall.
Reference: Internet. Type XN13-FA was first introduced in 1960.
Absolute Maximum Operating Conditions¶
Updated May 01, 2020. shape:thin.glass.tube construction:all.glass type:counter/indicator age:1960.1975 base: pin: