This category covers ultrasonic flaw detectors that use ultrasonic waves to non-destructively detect internal defects in metals, resins, composite materials, and other materials. They are used for detecting blowholes, cracks, and fusion defects in welded joints, voids and inclusions in castings, fatigue cracks in machined parts, and thickness measurement. Available in portable, benchtop, and automated scanning types, featuring A/B/C/D scope display functions, digital recording capabilities, and compatibility with various transducers. Unlike eddy current or magnetic particle testing equipment, these devices can identify the depth position of internal defects, which is their distinctive characteristic.