The IN-1 is a large Soviet nixie tube with an end-view envelope and phenolic base. The IN-1, unlike most other gas discharge displays, does not contain any mercury in it's fill gas, which substantially shortens the tube's lifespan. Under normal conditions, the number cathodes in an IN-1 will completely dissolve after only a few thousand hours of operation. The IN-1 is a larger nixie; digit height is 12mm and the tube has a diameter of 30mm and a height of 60mm. The tube's unusual 11 pin phenolic base is practically impossible to find a socket for, though the truly desperate can repurpose Molex pins from an ATX power supply to act as a socket stand-in. 

IN-1 is a cold cathode neon gas indicator displays digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 

Indicating current (no more than): 2.5mA; 

Keep-up voltage (no more than): 150V; 

Firing voltage (no more than): 200V; 

Length of the tube (without pins): 60mm; 

Diameter of the tube: 30mm; 

Symbol size: 0.74"x0.4" (18 x 10 mm).