02 sensor bolt size for 2002 2.7?

Anyone know the bolt size for the upstream 02 sensor on an 2002 tacoma 4x4 2.7?

On my way to work this morning the truck started to get a little loud. I found a safe place to stop and looked underneath and noticed the 02 sensor was just hanging down.

I've never seen an 02 sensor fall out before, but with 268k, anythings possible. I haven't crawled under it yet. I'm hoping the bolts vibrated out and did not shear (or rust) off.

The dealer parts dept will be closed
by the time i get out of work, so I'll have to try to get them at a hardware store.

Thanks in advance for pointing me in the right direction.

EDIT: just looked under it, I need the nuts, not bolts. The studs still look good. Anyone know what size the nuts are?

This weekend I'll fix it right and put in a new sensor & get gasket.

 

They are M8 x1.25 studs

If the nuts came off not to bad if the studs broke it could be interesting.

I have learned for me it is easier to remove the pipe weld in a new bung install new studs then fighting things on the truck.

 

Thank you.