At the very simplest level, Radio Frequency Identification (RFID) technologies allow the transmission of a unique serial number wirelessly, using radio waves. The two key parts of the system that are needed to do this are the RFID 'tag' and the 'reader'; attaching an RFID tag to a physical object allows the object to be 'seen' and monitored by existing computer networks and back-office administration systems. So far, the key driver for the development of RFID systems has been the desire to improve efficiency in globalised supply chains but implementation of the technology has been problematic. This is partly due to the manufacturing costs of tags, which are currently too high to justify widespread deployment across supply chains in the way that was originally imagined, and partly due to concerns over the potential for infringing the privacy of consumers who purchase RFID-tagged products. In addition, there are concerns about the health implications for staff employed in RFID-enabled workplaces, although this has not received as much attention in the press