This is a fully heat treated chromoly heim with a radial static load (RSL) rating of 76,200 lbs. The 52100 bearing is heat treated steel and hard chrome plated. The housing has a hard chrome finish. The race is made from a Teflon-impregnated nylon injection molding. 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 misalignment 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!