1.25" Rod End
This Heim has a 1.25" shaft with a 1" bore. The reason we use the 1" bore instead of a 1.25" bore is strength. There is simply more material on the 1" bore rod end and with a 3/4" bolt, after missalignment that is what you would end up with anyway. If you need a 1.25" rod end, you don't want a small bolt becoming the weak point. Sometimes smaller in the right places is better!