The threads are a 7/16-20 on the nut side of the stud and on the manifold side a 7/16-14. The unique feature of these studs are that they have an enternal broached hex that make installation a snap with a wrench. The hard anodizing helps prevent galling and the alum. provides light weight while providing a safety factor in the event of a supercharger backfire saving your supercharger or manifold.
It will not fit PSI, SSI, Folwer or Kobelco superchargers.