All GS and GL Balboa systems such as GS500 GS501 GS510 GS511 GS520 GS523 GL2000 GL2001 and GL8000. You will most likely find this style of connection on other electronic spa systems also.
Used to make the light connection. This connection is usually positioned so that you can connect components directly on to the PCB. Not shown in this picture but you can link this cable with another the same to extend the cable.