SparkFun COM-11143 Audio Plug – 3.5mm
This is a simple 3.5mm TRS stereo audio jack with a screw-on plastic shroud. These are great for projects that plug into headphone jacks. Stereo plugs can also be used for carrying serial comm connections!
The outer shell unscrews to reveal solder terminals on the inside of the plug. Solder on your wires and crimp the strain relief to make a finished, professional-looking cable.