1-Year WarrantyNote: This gauge can not measure the thickness of cast iron. Specifications: LCD digital display: 4 digits. Minimum display unit: 0.1mm. Working frequency: 5MHz. Measurement range: 1.2-225.0 mm (Steel). Minimum limit for tubes measurement: 20 x 3mm (Steel). Accuracy: ± (1% H + 0.1 mm) (H denotes the measured thickness). Sound velocity range: 1000-9999m/s. Measuring sound velocity with a given thickness. Measuring range: 1000-9999m/s. When the given thickness over 20 mm, the accuracy is ±1%; when the given thickness less than 20mm, the accuracy is ±5%. Operating temperature: 0 - 40°C (32 - 104 °F). Power supply: 3 x 1.5 AAA alkaline batteries (not included). Operation current: Normal operation current ‰¤ 50 mA. With backlight turn on current ‰¤ 120 mA. Stand-by current: ‰¤ 20 μA. Size: approx. 72 x 146 x 29 mm. (2.83 x 5.75 x 1.14 inches). Package includes: 1 x Ultrasonic thickness meter (with rubber cover)1 x Transducer (10 mm, 5 MHz) 1 x 4 mm Sample block 1 x Bottle of coupling agent (50 ml) 1 x Operating manual 3 x AAA alkaline batteries 1 x Storage box