The general pressure gauge is suitable for measuring the pressure and vacuum of liquid, gas or steam without explosion, crystallization, solidification and corrosion of copper and copper alloy.  The working pressure should be 1/3 to 2/3 of the full range, and the range of use should not exceed 4/3 of the full scale.  The verification period generally does not exceed half a year. If the medium in the pressure measurement part fluctuates greatly, is used frequently, has high requirements for accuracy, and has strict requirements for safety factors, the verification period can be appropriately shortened according to the specific situation.  The working environment of the pressure gauge should not be corrosive.