An electrical connector includes an insulative housing, first and second contact modules received in the insulative housing, a first metal shell covering the insulative housing and a grounding piece. The insulative housing includes a mating tongue and the first metal shell includes a plurality of peripheral walls enclosing the mating tongue to cooperatively form a mating opening therebetween. The grounding piece includes a number of side walls and a receiving opening through which the peripheral walls extend. The side walls include a number of half-spherical embosses stamped therefrom to abut against the front metal shell for EMI protection.