Display structure of pressure gauge of air compressor

A display structure of a pressure gauge of an air compressor, the air compressor being received in an accommodation box, and a scale portion of the pressure gauge being viewable via a displaying opening of the accommodation box the pressure gauge including a cylindrical body which is transparent and is formed in a pen shape, and the pressure gauge including a colored O-ring configured to indicate a pressure value of the scale portion;

• wherein the scale portion is not printed on the cylindrical body of the pressure gauge and includes a transparent panel on which the pressure value of the scale portion is marked on an internal face of the transparent panel, and the internal face faces the cylindrical body of the pressure gauge,
• wherein the transparent panel includes at least one first calibration unit and at least one second calibration unit, the at least one first calibration unit is defined by a cross, the second calibration unit is defined by a cross, the at least one first calibration unit and the at least one second calibration unit are printed on the internal face and the external face of the transparent panel respectively, such that a height difference and an oblique viewing angle are formed between the internal face and the external face so that a viewing sight is perpendicular to the scale portion, and the pressure value is viewable accurately via the internal face and the external face of the transparent panel,
• wherein the transparent panel of the scale portion is detachably connected with the cylindrical body of the pressure gauge, and the cylindrical body has at least one fixing rack on which at least one positioning bolt is arranged, such that the at least one positioning bolt of the at least one fixing rack of the cylindrical body is connected with at least one connection orifice of the transparent panel.