ELECTRICAL CONNECTORS FOR ATTACHING TO THE ENDS OF ELECTRICAL CABLES; OPTICAL COUPLING CONNECTORS FOR ATTACHING TO THE ENDS OF OPTICAL FIBER CABLES; PARTS AND FITTINGS FOR THE AFORESAID GOODS, NAMELY, BACKSHELLS, SPRINGS AND CLAMPS FOR SECURING THE BRAID OR SHIELDING OF ELECTRICAL AND OPTICAL FIBER CABLES TO THE BACKSHELLS OF CONNECTORS, PROTECTIVE SLEEVES AND BOOTS, STRAIN RELIEFS