A cable assembly includes a plurality of contacts, an insulation housing and a metal shell assembled on the insulation housing. The insulation housing is molded outside the contacts and includes a fastening portion protruding from a rear end of an upper surface of the housing, and a pair of side arms rearward extending from the two sides of a rear surface of the fastening portion. The metal shell is assembled on the insulation housing and located behind the fastening portion. The fastening portion is substantially of U-shaped configuration with a pair of L-shaped cutout located on the two sides thereof and the two cutouts faces toward the outside. The metal shell includes a pair of clasping portions respectively frontward extending from the front surface of two side walls of the rectangular frame. The clasping portions are respectively inserted into their corresponding cutouts.