A socket is one endpoint of a two-way communication link between two programs running on the network. A socket is bound to a port number so that the TCP layer can identify the application that data is destined to be sent to. An endpoint is a combination of an IP address and a port number. This set contains 1/2" universal joint, 1/2" sd pear head ratchet NP9, 1/2" sd 15" swivel handle, 1/2" extension 125 and 250 mm, and 1/2" standard socket 10-11-12-13-14-15-16-17-18-19-20-21-22-23-24-27-30-3. For additional information regarding the product, please contact with dubuy support team.