Accuracy levels: 1.5 and 2.5; Usage conditions: -20~+50 ℃, relative humidity ≤ 85%; Pressure resistance effect: When the self frequency constant value changes by ± 15%, the indication error does not exceed the basic error. Mechanical performance: able to withstand acceleration of 30 meters/second ², impact frequency of 80-120 times per minute, and two-hour transportation shaking. Working position: suitable for use in the vertical direction