5966K26 this is the part number for a 5/8" ball screw at 1.25 dollars an inch. (the cheapest and most economical size)
5966K16 this is the number for a sqare ball nut for the aformentioned screw. Also the cheapest and most economical on the list. These are what I have bought in the past.
ignore all of the letter stuff as they are just the dimensional specs. (unless you need them for your decsion
)
whats to understand?
I would verify my numbers as I don't want to miss lead you because of a typo or boneheadness on my part.