Simpson 20d x 4 in. Annular Ring Shank Box Nail in Type 316 Stainless Steel is built for construction professionals who need a fastener that holds firm and resists corrosion over the long haul. The annular ring shank delivers exceptional withdrawal resistance, making these nails a dependable choice for permanent wood foundations, coastal structures, exterior decking, and any application where moisture, salt air, or harsh environmental conditions would compromise a lesser fastener. Produced in the United States, this bulk pack is suited for demanding projects where fastener integrity cannot be left to chance.

Key Features

• Type 316 Stainless Steel construction - provides superior resistance to salt air, moisture, and corrosive environments, making these nails well-suited for seaside, coastal, and high-moisture applications where standard fasteners fail prematurely.
• Annular ring shank design - the ringed shank bites into wood fibers and dramatically increases withdrawal resistance compared to smooth-shank nails, keeping connections tight under load and over time.
• 8-gauge, 20d x 4 in. sizing - a heavy-gauge, full-length fastener that provides the structural depth and holding strength required for permanent wood foundations and exterior framing assemblies.
• Full round checkered head - the checkered head pattern accepts paints, stains, and surface finishes cleanly, making these nails appropriate for applications where coating adhesion and finished appearance both matter.
• Diamond point tip - designed for clean, consistent entry into wood, reducing splitting risk and making driving more efficient across a range of lumber types.
• Made in the United States - domestic production supports consistent material standards and quality control for professional and commercial construction projects.

Why This Product

• Engineered specifically for corrosive environments - Type 316 stainless steel is the recommended alloy for seaside and coastal construction, where salt air and persistent moisture accelerate corrosion in standard steel or lower-grade stainless fasteners, protecting structural integrity for the life of the assembly.
• Meets permanent wood foundation requirements - these nails align with the specifications called out in the ANSI/AF&PA Permanent Wood Foundations Design Specifications, giving builders and contractors confidence in code-appropriate material selection.
• Holding power that works with the wood, not against it - the combination of a heavy 8-gauge shank and annular ring profile means the nail resists backing out under cyclic loading, weathering, and wood movement - a critical advantage in exterior and high-stress framing applications.
• Finish-friendly head for professional results - the checkered full round head grips applied coatings rather than repelling them, so painted, stained, or sealed surfaces maintain a uniform appearance without fastener bleed-through or adhesion failures.

Specifications

• Model Number (MPN): T20ABNB
• Material / Coating: Type 316 Stainless Steel
• Gauge: 8
• Penny Size: 20d
• Length: 4 in.
• Head Diameter: 5/16 in.
• Shank Diameter: 0.162 in.
• Shank Type: Annular-Ring Shank
• Head Type: Full Round Head
• Head Pattern: Checkered
• Point Type: Diamond Point
• Packaging Quantity: 25 Lb
• Country of Origin: United States

Approved Applications

• Seaside and Coastal Construction: The Type 316 stainless steel formulation is specifically recommended for seaside applications where salt air and moisture accelerate corrosion in lesser materials.
• Permanent Wood Foundations: Stainless steel nails of this specification are recommended for construction of permanent wood foundations in accordance with the ANSI/AF&PA Permanent Wood Foundations Design Specifications.
• High-Moisture Environments: Suited for any application requiring superior corrosion resistance where long-term fastener integrity is critical.
• Decking and Exterior Framing: The annular ring shank and corrosion-resistant material make this nail appropriate for exterior wood assemblies subject to weathering and load stress.
• Applications Requiring Surface Finishing: The checkered head accepts paints, stains, and surface finishes, making it appropriate where aesthetics and coating adhesion matter.

What's Included

• Simpson T20ABNB 20d x 4" Annular Ring Shank Box Nails, Type 316 Stainless Steel - 25 Lb bulk pack

Frequently Asked Questions

Why is Type 316 stainless steel recommended over Type 304 for this nail?

Type 316 stainless steel offers superior corrosion resistance compared to Type 304, making it the preferred choice for coastal, marine, and seaside applications where constant exposure to salt air and moisture can rapidly degrade lesser materials. For structures built near the ocean or in high-humidity environments, Type 316 provides the long-term durability needed for the life of the structure.

What advantage does the annular ring shank provide compared to a smooth-shank nail?

The annular ring shank dramatically increases withdrawal resistance compared to smooth-shank fasteners. The ringed shank profile creates a more secure and lasting attachment in wood substrates, making these nails especially well-suited for applications where structural integrity cannot be compromised, such as permanent wood foundations, decking, and seaside structures.

What types of projects are these nails best suited for?

These nails are engineered for demanding construction applications requiring superior corrosion resistance and long-term holding power. Ideal uses include permanent wood foundations, decking, and coastal or marine structures where exposure to salt air, moisture, and corrosive elements is a consistent concern.

What does the checkered head pattern on these nails offer?

The full round checkered head blends seamlessly with wood grain, reduces glare from direct sunlight, and readily accepts paints, stains, and other surface finishes, resulting in a clean, professional appearance on finished surfaces.