This thickness gauge is an intelligent handhold product, which adopts ultrasonic measuring principle, and is controlled by Micro-processor, provides quick and precise measurement of thickness for most of industrial material. This product is widely used in various precise measurement for different hardware / parts in industrial realm; one of its important application is to monitor the level of thickness-de-creasing during operation of various and pressure container. Diffusely applied in manufacture fields, metal processing, and commercial inspection. The material that conduct and reflect constant velocity. Main Technical Specifications (based on file 1, rearranged in English) Measuring Range: 1.2 - 225.0 mm (steel) Display: 4-digit LCD Minimum Display Resolution: 0.1 mm Operating Frequency: 5 MHz Minimum Tube Size for Measurement: 20 x 3 mm (steel) Accuracy: (1 % of H + 0.1) mm, where H is the measured thickness Sound Velocity Range: 1 000 - 9 999 m/s Sound-Velocity Calibration Accuracy (with given thickness): 1 % when thickness Less than 20 mm 5 % when thickness 20 mm Operating Temperature: 0 C - 40 C Power Supply: 3 x 1.5 V AAA alkaline batteries (Not included batteries) Operating Current Normal: 50 mA Backlight ON: 120 mA Stand-by Current: 20 A Note:because if the product with battery, the customs not pass, so the product not include the battery, hope you can understand, thank you. Color: As Shown Material: plastic Package Contents: 1 * thickness gauge Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.