1)High accuracy and quality 2)Operation convenience 3)Competitive prices 4)Warranty one year and lifetime maintenance DT-445A DIGITAL ULTRASONIC THICKNESS GAUGE Measuring range (metric/imperial): 1.0-200mm,0.05-8inchOperating principle: ULTROSONICMaterials measured: any hard materials, including steel, cast iron, aluminum, red copper, brass, zinc, quartz glass, polyethylene, PVC, gray cast iron, nodular cast iron and other materials Sound velocity: 500-9000m/sLower limit steel pipes: 15x2.0mm, 20x3.0mm determined by the transducerCalibration block: includedAccuracy: ±(0.5%n+0.1)RS232C interface: with RS232C Power supply: 4x1.5V AAA (UM-4)batteryBattery indicator: low battery indicatorOperating conditions:0-+40°C(32°F-104°F),≤90%RHDimensions: 152x65x27mmweight: 185g(not including battery)