Truss rod wrench for SLSMG(yes I searched first)

[Thanatopsis]

So I'm trying to find a wrench to fit the truss rod on my SLSMG. I've tried searching online and have seen various answers. Now even with a flashlight, I can't even see in there if it's a square or hex head. I have two of those swiss army type allen things with a bunch of sizes, one imperial, one metric. Neither of those fit. I read a couple places it's square and my few square bits are either not the right size or simply not long enough. An answer from someone that owns one and can say for sure would be excellent. Otherwise what I'm probably going to do is just bring my guitar to Lowes and figure it out there. If they don't like me doing that, then they're going to have to process a few of returns after I buy a various sizes and return all the ones that don't fit.

[warlok]

I swear I remember hearing somewhere it was a 5/16 hex nut (not allen).. Try a 5/16 socket and report back..

[warlok]

Did you try it or find the correct one?

[Thanatopsis]

I haven't made it to the store yet. Going to try to go tomorrow.