Features: Large digital display screen, clearer reading: LCD display with high transparency, scratch resistant and wear-resistant surfaces. Ratchet constant forces controling mechanism, stable, accurate and reliable measurement: ensuring constant rotational forces to prevent measurement errors caused by excessive forces application. Lasers precise marking, can read even without power: Even after four rounds of lasers marking, it is still clear and visible. Upgraded precisions sensors, double engines power: level double sensors ensure precise sensing, with a high-precisions power source of 0.001MM. High hardness tungstens steel measuring head, not easy to rust and wear: Select high hardness tungstens steel material to resist corrosion and wear, with a longer service life. Upgraded to a 3V large lithiums battery, doubling the battery life. Upgraded bluetooth-compatible chip, fast response: fast and accurate transmission efficiency, no delay or lags, with a transmission distance of 10meters. Waterproof, dustproof and durable, with a longer service life: 6-level dustproof and 5-level waterproof, oil resistant, suitable for use in harsh environments. Specifications: Material:Steel Measurement Ranges: 0-25mm/0-1'',25-50mm/1''-2'',50-75mm/2''-3'',75-100mm/3''-4'' Resolution: 0.01mm Note: Please allow 1mm errors due to manual measurement. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x External Micrometer