Ultrasonic Wall Thickness Gauges (also known as ultrasonic thickness testers, ultrasonic thickness meters, or UT gauges) use ultrasonic technology to measure the wall thickness of materials such as steel and plastic. Ultrasonic thickness gauges are suitable for assessing the impacts of corrosion or erosion on tanks, pipes, or any structure with limited access on one side. Multiple echo Thru-Paint models (UTG M) can measure the metal thickness of a painted structure without removing the coating.