3.5mm (1/8") 4-Pole (TRRS) Audio Plug Terminal Block
One truth about working with audio is you always need the cable or adapter you don't have in your toolbox. That's why we love these terminal-block audio connectors so much. No soldering required! Use stranded or solid core wire and a small screw driver to create custom wiring jigs.
This is the 3.5mm (1/8") 4-Pole (TRRS) Audio Plug Terminal Block. TRRS stands for Tip, Ring, Ring, Sleeve. It has four total conductors - three signal and a ground as opposed to a more common stereo jack's two. This connector is most often used in smartphones & cellphones to provide stereo audio and one mic channel. On a Raspberry Pi the extra connector is used for composite video.
Note that the green block labels it as GND-blank-Right-Left which is the most commonly used order. However, it would be more technically correct to just label it Sleeve-Ring-Ring-Tip: goes in the same order as the four contacts on the plug.
May come with nickle or gold plated contacts.