Shield

Used in a cable to provide a protective layer of the signal conductors from EMI (Electro-Magnetic Interference) and RFI (Radio Frequency Interference). The shield works by providing a low-resistance path that collects the stray interference signals and grounds them to earth so that they do not get into the signal wires. There are two types of shields used in cables; a foil shield, and a braided shield. When both are used in a cable, it is called a double-shield, or foil and braid.