 Manufactured by Sperry Corporation, the testing device was known variously as the Firestone-Sperry Reflectoscope, the Sperry Ultrasonic Reflectoscope, the Sperry Reflectoscope and sometimes also just as a Supersonic Reflectoscope, the name Firestone had originally coined for the instrument.The technology is not just used in quality control in factories to reject defective parts before shipment, but also revolutionized transportation safety.For example, ultrasonic testing is used for safety maintenance inspection of railroad cars, particularly axles and wheels, aircraft, particularly fuselages, and other transportation vessels for material fatigue.