The GS-16A is a cold cathode symbol indicator with a common anode. The gas filling is probably neon and thus giving an orange glow around the selected cathode.
The anode is the outer mesh with the wire cathodes stacked within.
This tube will display +, -, sine wave and a spiral.
The base has 13 wires sealed into it but only six protruding wires. These wires can be seen to have the remains of printed circuit copper pads where this has been rescued from a defunct piece of apparatus.
The thin glass tube envelope is 18 mm in diameter, and excluding the base wires is 41 mm tall.
Updated November 01, 2015.