Connection technologies generally fall into one of three categories; screw, crimp, and spring connections.  Screw connections, as the name implies, utilize a screw that is tightened to retain the wire after it is inserted into the connector or terminal.  Crimp connections require a separate contact be applied to the prepared wire.  It is typically this contact that makes the connection.  With a spring connection, the wire is held in place with the tension created by metal formed to provide a spring like mechanism.  In the cases of both screw and spring connections, the prepared wire, either stripped of insulation or stripped with a ferrule applied, is inserted directly into the connector, terminal, or other device.  Spring connections in general offer significant advantages over the ever popular screw type.  They eliminate the requirement for periodic tightening of the screws and offer excellent resistance to vibration.  Additionally, tension clamp connections improve installation wiring efficiency by eliminating the need to properly torque screw actuators.  Push-in connectors go a step further by eliminating the need for a screwdriver to hold the clamp open during wire insertion.