3/4" Stainless Steel Screw Pin Anchor Shackle - 4 TonsType 316 Stainless Steel Shackles Type 316 stainless steel shackles are built to handle the challenges of high humidity and marine environments. Their enhanced corrosion resistance is due to a higher chromium content, which forms a protective chromium oxide film on the surface. This passive layer prevents corrosion from spreading deeper into the metal, making these shackles a reliable choice for saltwater, coastal, and chemical exposed applications.