A lot of drive lines are 12 point 3/8,1/2,12mm. Then you have 6 point 5/16 ,7/16,16mm,17 mm, 18 mm. Then there are torx, hex( allen), and inverted torx. And what I have heard but not seen is a 23 mm drive live bolt. I drive a wrecker and remove a lot of drive shafts to tow them.