2 jack screws, self-tapping cover screws and cable clamp. Screwdown Metallised ABS Backshells. The RS Pro backshell covers allow for either top or side cable entry. A lightweight ABS housing is nickel plated to optimise EMI/RFI shielding effectiveness. The backshell provides the perfect balance between durability and economical considerations.. Features and Benefits. Lightweight ABS housing, nickel plated. Covers with removeable knockouts. Top or side entry