... ,0.05-8inchOperating principle: ULTROSONICMaterials measured: any hard materials, including steel, cast iron, aluminum, red copper, brass, zinc, quartz glass, polyethylene ... iron and other materials Sound velocity: 500-9000m/sLower limit steel pipes: Dia15x2.0mm, Dia20x3.0mm determined by the transducerCalibration block: includedResolution ...