IN-18:

Gas discharge display for numerical presentation of electronic signals.
Cathodes - in the shape of Arabic numbers (0 through 9).
Height of digits: 40 millimeter. [Inchlanders: 1.57" - Nebulus]
Display through side of bulb.
Case (?): glass.
Mass: 35 gram. [Inchlanders: 1.225 ounce - Nebulus]

Pin assignment:

1,8 - No Connection
2 - Number 4
3 - Number 5
4,12 - Anode
5 - Number 6
6 - Number 7
7 - Number 3
9 - Number 8
10 - Number 2
11 - Number 1
13 - Number 0
14 - Number 9

Specifications:

Brightness: >= 50 cd/m^2 [Inchlanders: 4.5 cd/sq ft - Nebulus]
Angle of visibility: >= 90 deg
Power supply voltage (?): >= 200 V
Discharge appearance voltage: <= 170 V
Discharge ??? voltage: <= 150 V [Notice: For the IN-17 it was >= 105 V!]
Display current: <= 4 mA
Operations current:
Running from DC: 4 - 7 mA
Running from AC with 50 Hz
(average value): 2 - 4 mA
Life time: >= 5000 hours