HomePlug Powerline networking is based on the concept of 'no new wires'. HomePlug is a standard for using existing electrical power lines in homes and offices to build computer networks.
Essentially Powerline is the Ethernet using power lines instead of network cables for data transmission.
Just plug a HomePlug into a plug socket and attach the outgoing cable into a Ethernet or USB port (depending on the HomePlug option you choose) on your computer. The HomePlug transmits data from your computer over the power lines to another HomePlug located within the same internal power grid establishing a network connection. From the second HomePlug any standard network device (2nd Computer, ADSL Router, Cable Modem, Switch, Hub etc...)
This pack contains 1 HomePlug, a network cable, instruction manual, and Windows software if you wish to use the security feature. These units are sold as singles, you will require at least two to create your network. The image shows front and back views of the units.