A 7 pin PLUG will fit a 12 pin SOCKET so unless you want to add wires for a fridge (unwise as too small) there is little reason to use one.

Far better to buy some 8 or 6G cable and use Anderson plugs which are heavy enough to prevent voltage drop.

I had twin Andersons with 6G (commonly called 6 B & S) cable to van batteries and Fridge