... mm Ultrasonic Thickness Gauge1. Suitable for measuring metal (such as steel, cast iron, aluminum, copper, etc.), plastic, ceramic, glass ... EL backlight; Measurement Range: (0.75 ~ 300) mm (steel), metric and imperial free conversion;Sound Velocity Range: (1000 ~ ... alloy case, certificate of inspection, operation instruction manual. LK300 Steel, Cast iron, Aluminum, Copper Ultrasonic Thickness Gauge