Specification: Display: 4-digital LCD display Minimum display unit: 0.1 mm Measuring range: 1.2 to 225.0mm (steel) Working frequency: 5MHz Accuracy: (1%H+0.1)mm,H denotes the measured thickness. Minimum limit for tube measuring: 20*3mm (steel) Sound velocity range: 1000 to 9999 m/s Measuring sound velocity with a given thickness: measuring range: 1000 to 9999 m/s. When the given thickness > 20mm, the accuracy is +/-5%; when the given thickness < 20mm, the accuracy is +/-1mm/H*100%. Operation Condition temperature: 0°C~40°C Relative humidity: <90%RH Hardware/workpiece/material temperature: <60°C Operation current: Normal operation current: 50mA With Backlight turn on current: 120mA Stand-by current: 20uA Packing Contents Thickness Gauge-1PCS transducer-2 PCS(10mm 5MHz ) Storage Bag 4mmSample block-1PCS Power supply: 1.5V AAA * 3 PCS (not include due to air limit) Minimum limit for tube measuring Dia.20*3mm(steel) Auto Zero Calibration V Auto linear compensation V Coupling Indicator V Metric / Imperial Switchable --- Battery Indication / Auto Power Off V Product Net Weight / Product Size Size 158*62*30mm/6.2*2.4*1.2in Weight Approx.746g/26.3oz Table of sound velocity (Sound velocity of common materials) Material Velocity(m/s) Material Velocity(m/s) Aluminum 6320 Acetate resin 2670 Zinc 4170 Phosphor bronze 3530 Silver 3600 Turpentine 4430 Glod 3240 Glass 5440 Tin 3230 Incoloy alloy 5720 Iron/Steel 5900 Magnesium 6310 Brass 4640 Monel alloy 6020 Copper 4700 Nickle 5630 SUS 5790 Steel 4330 mild 5850 Acrylic resin 2730 Steel 330 5660 Water 20C 1480 Titanium 6070 Glycerinl 1920 Zirconium 4650 soluble glass 2350 Nylon 2620 Package list: 1 x Thickness Gauge 1 x 4mm Calibration Block 1 x Probe (10mm 5MHz) 1 x Storage Bag