The GR26-16 is a small voltage stabiliser made by Otto Pressler of Leipzig. The striking voltage is 200 Volts and the regulation range is 140 - 180 Volts for currents of 3 - 15 mA. The GR26-12 is the same regulator but on a miniature bayonet base.
Both cylindrical electrodes are made of mesh.
The B7G base pins. The evacuation pip can be seen inside the base.
The woven mesh electrodes.
With support only at the pinch, the middle electrode is not perfectly central. The cylinders can be seen not to close.
The thin glass tube envelope is 16 mm in diameter, and excluding the B7G base pins is 64 mm tall.