Extech Digital Ultrasonic Thickness Gauge, 1 to 508mm

Wide measurement range: 5MHz probe: 0.040 to 20 of steel, 10MHz probe: 0.020" to 20 of steel (optional) Suitable for use both indoors and outdoors Measures the thickness level of steel-based structures and other materials Sunlight readable dot-matrix display with backlight Multiple transducer options for high temperature and difficult to measure materials Fast minimum feature to capture minimum thicknesses