An electrical connector including an insulative housing having an elongated base and a pair of end sections each with opposite top and bottom surfaces, opposite front and rear surfaces. The shell includes a base plate covering the top surface at two opposite end sections of the base. Each end sections further includes a receiving cavity for receiving the retaining piece, and a slit communicatively beside the receiving cavity. The shell includes a pair of fixing tabs located at two opposite ends and respectively extending into the slits so as to interfere with the corresponding fastening nut for reliably positioning the fastening nut in the receiving cavity and being adapted to absorb the forces applied upon the fastening nut.