i am wiring a USB water resitant socket into the dash. i have it mounted and am about to wire it.

this is it
IMG_2072_Fotor.jpg

under the left service cover i found this.
is this a 12v keyed power source?
IMG_2069_Fotor.jpg

assuming that this will be my power source, i need some wire.
i have some 16 awg cl3 stranded copper direct bury that i used for a class 2 circuit. would that work for supplying power to this outlet?

as a side note, what is this connection for?
IMG_2071_Fotor.jpg

thank you for any help,
ba