The Elka 22 is the first Bulgarian electronic calculator; it was released in 1965. Weighing 8.5 kilograms (18.7 pounds), the Elka 22 has 3 registers and operates with 12 decimal digits. Addition speed is 0.3 seconds per operation, and division speed is 0.5 seconds. Its power consumption is 35 watts.
Image source: Soviet Calculators Collection