An electrical connector for inserting along a mating direction into a receiving space of a complementary connector through an insertion hole of an electronic device that has a dimension greater than that of the receiving space includes: an insulative housing; plural contacts secured to the insulative housing; and an outer shell enclosing the insulative housing, the outer shell including a front portion and a rear portion each having a respective lateral dimension measured along a transverse direction perpendicular to the mating direction, wherein the lateral dimension of the rear portion is greater than the lateral dimension of the front portion, the front portion is adapted to match the receiving space of the complementary connector and the rear portion is adapted to match the insertion hole of the electronic device, and the lateral dimension of the rear portion is less than the electronic device insertion hole dimension.