Vintage new old stock Russian made IN-15b Symbol Tube. This tube displays the following characters;

Hz, F, W, A, Ω, S, V, and H. 

Minimum supply voltage= 170 V

Typ. Maintain Voltage = 140 V

Typ. Cathode Current = 3mA

Character Height = 18mm

Overall Dimensions= 21mmx31mmx35mm

Uses SK-136 socket