Made of premium stainless steel, good strength with stable characteristics and high reliability. Depth dimensions can be measured easily and accurately. Adjustment `0'' at any position, mm/inch measurement system conversion. Quick display of the measured value on the screen, no overspeed error. Digital calipers for easy, direct and clear reading. Less accurate error, more accurate reading. Digital direct reading, can quickly return to zero, clear and convenient measurement, accurate. Made of high quality stainless steel, it is not easy to rust and prolongs the service life. The scale is delicate and clear, the practicability is high, the main ruler has meticulous workmanship, firmness and durability, and has a long service life. The attached conversion table is practical for conversion, which is used for depth measurement, groove width ruler measurement and groove position size. The nut is rotated to adjust the tightness , which can be fixed and measured, and can be used flexibly. One-key conversion, zero at any position, more convenient and efficient measurement. Button battery, convenient and fast, long battery life. Zero method First wipe the measuring surface of the ruler frame and the measuring surface of the body of the ruler, find a smooth and flat plane, make the measuring surface of the measuring claw contact the plane, and the observation reading should be zero. If it is not zero, press the zero switch to clear it. Metric/inch system: it is more convenient to convert with metric and English comparison table, and it is more convenient to measure with thumb pressure. Easy to read: digital caliper, fast reading, practical, direct and clear display. Large capacity battery: life of the longer battery: using 2 LR44 batteries (not included), large capacity, high performance and longer battery life, reducing the trouble of frequent battery replacement. Easy to carry : small size, light weight, easy to carry