I think a 1/2inch and a 12mm would be a better match then a 12inch to 13mm!
You mean 1/2inch, not "12inch" I assume?
Sorry, but your'e wrong. Go check it out for yourself... bet you a beer!
A 12mm socket is too small to fit on a 1/2" nut, and a 1/2" wrench is too big for a 12mm nut. 13mm and 1/2" are almost exactly the same size.
Nitpickers...