This DC power jack is added at the end of wires to connect with DC female barrel jack. This jack is compatible with a 5mm female barrel jack which has a 2.1mm centre pole diameter. The wires can be directly soldered or crimped to the terminals of the connector. You just have to unscrew the outer layer to reveal the solder terminals. SPECIFICATION Supply Voltage 5-30V Maximum Current 1A Colour Black DC Plug-in jack 5.5mm Quantity 1 Country of Origin China