To ensure quality, welds are tested using an ultrasonic flaw detector.

The rail flaw detector car was invented by Dr. Elmer A. Sperry.

Olympus manufactures and sells industrial scanners, flaw detectors, probes and transducers, thickness gages, digital cameras, image analysis software, industrial videoscopes, fiberscopes, light sources, XRF and XRD analyzers, and high-speed video cameras.

As a pioneer of NDT products company, SIUI released a series of digital ultrasonic flaw detectors in 2008 and developed China's first phased array ultrasonic flaw detector in 2009.