I think it was heavy wall 1 1/4" pipe. It fits snug(had to pound it in). I then tack welded the ends but I suppose you could bolt it. You will have to cut off the ends though which means the stock bumper is out. I do have a hard time calling that thing a bumper, more of a tin turn signal/license plate holder.
Ahh the plot thickens..... So to get to the tube to reinforce it you have to loose the front bumper anyhow

I know I looked at a Sami for sale that had a small HF winch bolted directly to that cross bar, then a hole cut out of the bumper with winch flaring bolted directly to the bumper, er I mean, tin turn signal/ license plate holder.... I guess it was just for looks huh? I wonder if it was even hooked up to the battery?

OK, I know I have seen old Sami brochures that have the same brush guard I have, but also have a small tray with a winch on them. Maybe that is what I need to do....