3 Units of Measurement - The electronic caliper has 3 units of measurement: mm/inch/fraction. You can change the unit as you like by pressing the "MM/IN/F" button. The measuring range is 0 - 6''/ 0 - 150mm; an accuracy of ±0.001"/0.02mm and a resolution of 0.0005"/0.01mm. Note: Measurements may have an error of ±0.02mm/0.001 inch. Quality Measuring Tools - The stainless steel material makes it very sturdy and durable, waterproof and rustproof can measure in different environments. You can measure with high accuracy by pressing a button or adjusting a screw. Auto On/Off - The LCD screen will automatically turn on when you are measuring, and automatically turn off the caliper if you do not use it for a few minutes. This helps to save battery and extend the usage time. Multiple Measuring Modes - 2 sets of jaws and 1 probe allow the calipers to easily measure the depth, length, outer and inner diameter of objects. It is a perfect measuring tool for jewelry lovers, woodworkers and crafters.