A plug connector includes a front housing, a first and a second terminal module each including an insulator insert molded with terminals. The front housing defines a rear wall, a front mating cavity opening forwards, and a plurality of terminal passageways running through the rear wall in a front and rear direction and the front housing in a vertical direction a first terminal module, The terminals comprising contacting portions received in the corresponding terminal passageways. The shell fitly encloses the front housing and the insulators. The front housing unitarily defines a plurality of protection flanges, each protection flange is located above a front end of each terminal passageway and each contacting section is located inside the protection flange thereby ensuring the contacting sections separating from the shell during the contacting sections are pushed outwards by an insertion of a mating receptacle connector.