uh you know there's something funny that i haven't really resolved with metric i've got to really go to the store and see if it's true i can't remember the size i think it's uh eighteen or something like that i have a set of metric and and the old wrenches too and i think that's an exact size of the three-quarters and they don't make it in metric they just skip over it and it
I don't remember the size.
They apply tension to that iron bar once they get the foundation poured, that in turn compresses the concrete, and makes it more stable, puts the strength into it.