A convertible vehicle has a car body having a rear vehicle area with a trunk. A pair of covers engages in a rotatable manner with the insulating housing for covering the respective insertion spaces, and two groups of terminals are respectively disposed in the two groups of terminal slots of the insulating housing. The mask set of the present invention further comprises a second mask consisted of a mask substrate on which a plurality of unit patterns are formed. Electrode posts are formed so as to pass through the outer periphery wall section and the ceiling section.