Simpson Strong-Tie S8ACNB - 2-1/2 x. 131 Ring Shank 10Ga 304SS 25lb. Simpson Strong-Tie S8ACNB 2-1/2 x. Annular ring shank increases withdrawal resistance to provide a secure attachment. Stainless-steel nails are recommended for construction of permanent wood foundations by the. ANSI/AF&PA Permanent Wood Foundations Design Specifications. Choose Type 316 stainless steel for seaside applications and superior corrosion resistance.