An electrical connector includes a mating portion including a first cavity (13) and a second cavity (11) divided by a partition (17). The first cavity (13) is structurally different from the second cavity (11), the first cavity (13) being of an L shape including a vertical alignment part (15) positioned proximate to the partition (17), while the second cavity (11) has no vertical alignment slot, which is removed to make the insulative housing (10) to have a greatly-reduced lateral dimension thereof so as to mount the insulative housing (10) onto a limited space of a printed circuit board.