Satisfaction Guaranteed:Welcome to contact us via E-mail iff you have any problem. Premium Material: Won?t scratch your valuable objects when measuring, serve you for years. Accurate Reading: Strictly tested to ensure exact measurements which accurate to 0.01 inch. Zero Calibration: Press to set to zero at any position and continue to measure next section. Unit Conversion: Easy to read in inches and mm by pressing the blue button on the top. Large LCD Display: Shows instant readings with digital numbers, much more convenient. Auto On/Off: Auto turns on when sliding, auto turns off after 5mins if with no operation. 4 Ways of Measurement -External Measuring: Measuring the outer diameter of objects with the long jaws. -Internal Measuring: Measuring the inner diameter of objects with the top jaws. -Depth Measuring: Measuring the depth of hard-to-reach small objects with the long probe. -Step Measuring: Measuring the height/length with its step design. CAUTION 1. Before first use, please remove the white insulation strip in the battery cover, or the electronic caliper cannot work. 2. The digital caliper is only for household measurement, such as jewelry, gadgets and other household objects. If for industrial measurement, please buy a more professional and more accurate measuring tool in professional field. 3. If you find the readings are not accurate, please slide the LCD screen to the left end (?0? on the scale), and then press the zero button. Welcome to contact us for more questions. Specifications: Material: Carbon Fiber Composites Size: 9.4 x 3 x 0.6in Weight: 2oz Measuring Range: 0-6 inches/0-150mm Accuracy: ±0.2mm/0.01? Resolution: 0.01?/0.1mm Battery: 1.5V LR44 button cell Package 1 x Digital Caliper 2 x Batteries