A Faraday bag is designed to shield a mobile phone or small digital device from radio waves entering the bag and reaching the device, or to stop radio waves escaping through the bag from the device. The effectiveness of these shields is vital for security professionals and forensic investigators who seize devices and wish to ensure that their contents are not read, modified or deleted prior to a forensic examination. This research tests the effectiveness of several readily available Faraday bags. The Faraday bags tested are all available through online means and promise complete blocking of all signals through the bag. Additionally, other materials that can be used if a Faraday bag is not available, such as tin foil and a tin can are tested and compared with the Faraday bags. A selection of common mobile phones from various manufacturers is tested in the shielding material. Additionally, 3G / 4G, WiFi and Bluetooth are tested with the bags and materials on those so equipped devices to ascertain whether the material blocks all signals from communicating technologies on the phones. Results show that performance of the bags is not as promised by most vendors and that in urgent situations other materials at hand may suffice to perform the same function as a Faraday bag.