This is a 5/8" shaft with a 5/8" bore & Right Hand Threads (18TPI). Sometimes smaller in the right places is better! Don't let the price confuse you, these are a very high quality Heat & Cryo treated Chromoly rod end, they are definately not a cheap mild steel heim. The housing has a hard chrome polished finish and the Ball is made from 5200 bearing steel and heat treated with a hard chrome finish. The race is made from injection molded Nylon. Ultimate Radial Static Load - 21,000lbs. These are not tested to breaking point, they are tested to first deformation, that is a key point, deformation is not breaking. The other companies test to destruction, I believe if they tested using the same methods the results would be very close, if not the same.