Ultrasonic thickness gauges are devices used to measure the thickness of materials, particularly metals and plastics. They work by emitting high-frequency sound waves that travel through the material. When these waves hit the opposite side, they reflect back to the gauge, allowing it to calculate the thickness based on the time it takes for the sound to return. These gauges are commonly used in various industries, including manufacturing, construction, and aerospace, to ensure structural integrity and safety. They are especially useful for detecting corrosion or wear in pipes and tanks, providing accurate measurements without damaging the material being tested.