This is a kit that includes eight heat treated twelve point steel nuts, eight AN washers and eight hard anodized alum. studs. This kit fits all PSI, SSI, DMPE, Fowler or Kobelco roots superchargers.
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 internal broached hex that make installation a snap with an Allen 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.