Dual Thickness Meter Gauge Wave velocity 1000~9999m/s for steel, Aluminum, Copper, Glass Measuring thickness of various good ultrasonic wave conductors such as steel, aluminum, copper, glass It measures the thickness of ultrasonic wave well-conductive material Selectable thickness unit, "mm" or "inch" Measurement Range: 1.2~220mm (steel) Ultrasonic wave velocity: 1000~9999m/s