A plug connector includes a plug housing (11) defining a receiving space (1110), a plurality of contacts retained in the plug housing, a cable (16) electrically connected with the contacts and a shielding member (15) enclosing on the plug housing to form a cavity. The contacts comprises a plurality of first contacts (12) and a plurality of second contacts (13), stiff contacting portions of the first contacts are exposed in the receiving space, and elastic contacting portions of the second contacts are exposed in the cavity for transmitting high speed signal. The shielding member is enclosing on the plug housing to form a cavity, the cavity is stacked on the receiving space. The slit is communicated with an exterior in the up-to-down direction, the plug connector further comprises an additional contact (18) received in the slit and extending beyond the bottom surface of the plug housing.