As the original pioneers, Cygnus Instruments has developed digital multiple echo technology to obtain accurate thickness measurements through coatings and corrosion. Cygnus now carries 3 product lines:  Ultrasonic Thickness Gauges, Ultrasonic Hatch Cover Weather Tightness Tester and Ultrasonic Flooded Member Detector.
Elcometer has Ultrasonic Thickness Gauges, Precision Thickness Gauges, Flaw Detectors and Bolt Tension Monitors.