Factory box ?

[5.0 from 95]

I have the factory box for the rear speakers still in the car with upgraded speakers in it. My question is, there are 4 studs that stick down, the box goes on and then you have 4 nuts that hold the box in place, what size socket will fit on these nuts? I have vibrated 2 out and I can not find them and I can not get to the front 2, because of my sub box, and the rattling is driving me crazy. Thanks in advance.


Paul