Inexpensive thickness gauge for steel, cast iron, aluminium, copper, brass, zinc, quartz glass, polyethylene, PVC, gray cast iron, spheroidal iron. They are usually used to determine the thickness of tanks, sheet metal, pipelines, vacuum vessels, bulkheads, etc. they are often used in quality control activities and maintenance inspections to detect corrosion on the workpiece. The instrument can be supplied with various optional probes depending on the application area.