1. It is suitable to use at ambient temperature of - 25 ~ 55 C. It is advisable to use the sealed rubber stopper on the upper part of the watch case to cut off the sealing rubber stopper so that the inner cavity of the instrument can communicate with the atmosphere, because the ambient temperature is too high and the indicating value of the instrument does not return to zero or the indication value is too bad

2.  The gauge should be used in a range of 1/3 to 2/3 of the upper limit. When using, the valve should be opened slowly so that the pressure rises slowly to the working position. If the valve is suddenly opened, such as pressure out of control, beyond the upper limit of measurement, the spring tube will be damaged, deformed or the fan teeth will be detached and the instrument will lose function.

3. After use, the pressure should be slowly relieved, and the pointer should not be suddenly reduced to zero, so that the pointer will hit the disc stop nail, which will bend or even break the pointer.