The GR22-12 is a neon voltage stabiliser with mesh electrodes and a small bayonet base. The GR-22-10 is the same device fitted with an IO base cap.
The ignition voltage is 200 Volts and the tube drops 130-170 Volts for currents of 10 to 60 mA. The anode is the outer ring.
This tube was purchased in 2015 for experiments in optical communication. With the neon glow arranged around the central electrode and driven by a modulated current source good results were obtained over several tens of feet.
The mesh cylinders mounted on the pinch.
The outer cylinder is the anode and in normal use the glow and thus the heat is formed around this larger diameter tube.
The wide glass tube envelope is 28 mm in diameter, and including the bayonet base is 90 mm tall.
Updated July 29, 2015.