... for optionCONDITIONS1) Environment: away from rain, sun, high temperature, dust, alkali, acid, strongvibration situation or strong electromagnetic ... ) Relative humidity: 10% - 90% 4) Noise: <60dB 5) Temperature: -10°C - 40°C TECHNOLOGY STANDARDS1) Timing accuracy: <1 sec2 ... : ≤0.5dBNOTICE1) Meter should work in ventilated and clean surrounding. Be away from rain, sun,high temperature, dust, alkali, ...