Manufactured by J.B. Carroll Company, Illinois. Computer - Air Navigation, True Air Speed, Mach. No. Wind Components, Supersonic, Air Force Type MB-2A. Part No. 205. According to the handbook this dead reckoning computer is an 11cm diameter circular device for obtaining the solution of the following type problems : True airspeed, mach number, temperature rise, time and distance, ground speed, fuel consumption, density altitude, relative wind, drift angle, true altitude, pressure pattern, drift and cross wind, standard atmposphere, velocity of sound, interception, radius of action and critical point. Comprised of three plastic concentric discs operating on a circular slide rule principle. Excellent condition with full markings. Complete with original case and 32 page handbook of operating instructions. Stock code 23203.