KWR Zip-lock foil shielding bags. Zip-lock foil shielding bags are widely used for anti static protection when storing and transporting sensitive electronic circuits or components. The zipper lock closes securely to protect against dust and moisture. These bags work on the Faraday shield principle, a Faraday Shield (also known as faraday cage) creates a protective barrier from electrostatic charges protecting items inside the bag from harmful static charges. Similar to a conductive tote box with a lid, a shielding bag creates a protective enclosure that shields items from harmful static charges. Bags carry the identification logo as a reminder that their contents are sensitive to static electricity.