Thickness gauges are instruments used to measure the thickness of materials, such as metals, plastics, and coatings. They are essential in various industries, including manufacturing and construction, to ensure that materials meet specified standards and tolerances. Common types include ultrasonic thickness gauges, which use sound waves, and magnetic thickness gauges, which measure the magnetic properties of materials. These devices can be handheld or integrated into production lines, providing quick and accurate measurements. Thickness gauges help prevent defects and ensure quality control, making them vital for maintaining safety and performance in products like automobiles and aerospace components.