Simpson Deck-Drive DWP Wood Screw in Type 305 Stainless Steel by Simpson is engineered for deck, dock, and general exterior wood fastening applications where reliable corrosion protection is essential. Featuring a trim head profile, T20 6-lobe drive, and sharp point tip, this #9 x 4" screw drives cleanly into wood decking, fascia, and trim boards with minimal splitting or surface damage. The Type 305 stainless steel construction resists rust and oxidation in outdoor environments, making it a trusted choice for exterior structural and finishing work where weather exposure is a constant concern.

Key Features

• Type 305 Stainless Steel material - resists corrosion and oxidation in outdoor, exposed, and moisture-prone environments, extending the service life of your fastened assembly
• Unique box thread design with raised-ridge technology - greatly reduces driving torque so you can drive more screws per battery charge, improving efficiency on large decking projects
• Specially designed sharp point - penetrates hardwood and dense wood products with ease, reducing the need for pre-drilling and speeding up installation
• T20 6-lobe drive - provides a secure bit fit for easy, consistent driving and extended bit life, reducing cam-out and driver wear over the course of a project
• Trim head profile with 0.250" head diameter - sits flush or countersinks neatly into decking and trim surfaces for a clean, low-profile finished appearance
• Compatible with wood, engineered wood, and polymer materials - versatile enough for a wide range of modern deck board types, fascia, millwork, and exterior trim applications
• 4" length in a #9 screw size - provides deep penetration and strong holding power through thicker deck boards and into structural members beneath

Why This Product

• Designed specifically for decking, dock, and boardwalk applications - the combination of sharp point penetration and box thread technology means less effort driving each fastener, whether you are working with standard lumber or engineered wood products
• The Type 305 stainless steel finish delivers meaningful corrosion resistance for exterior projects exposed to rain, humidity, and seasonal weathering - making it well-suited for decks, docks, and outdoor structures away from direct saltwater exposure
• The trim head keeps the screw face small and low-profile at 0.250" in diameter, which is ideal for fascia, millwork, and finishing work where a neat surface appearance matters alongside functional strength
• Available in a variety of sizes for both structural decking and trim or fascia fastening - a single product family that covers the most common exterior wood fastening needs on a job site

Specifications

• Brand: Simpson Strong-Tie
• Screw Size: #9
• Length: 4 in.
• Head Type: Trim Head
• Head Diameter: 0.250 in.
• Drive Type: T20 6-Lobe
• Thread Type: Box Threads
• Point Type: Sharp Point
• Material: Type 305 Stainless Steel
• Finish: Type 305 Stainless Steel
• Approximate Count Per Lb.: 61
• Country of Origin: Taiwan

Available Pack Options

• S09400WP1: 1 Lb - includes (1) T20 6-lobe driver bit
• S09400WP5: 5 Lb - includes (1) T20 6-lobe driver bit
• S09400WPB: 1000 Pk - includes (2) T20 6-lobe driver bits

Approved Applications

• Wood deck boards and decking surfaces
• Docks and boardwalks
• Exterior fascia and trim boards
• Millwork and finishing applications
• General exterior wood fastening where corrosion protection is required
• Engineered wood and polymer deck board products

Frequently Asked Questions

What type of wood and decking materials is this screw compatible with?

The Deck-Drive DWP Wood Screw is designed for use with wood, engineered wood, and polymer materials. Its sharp point and box thread design make it well-suited for the majority of wood used in today's deck boards, as well as fascia, trim, and millwork products used in exterior applications.

Why does the box thread design matter for a decking project?

The unique box thread design incorporates raised-ridge technology that greatly reduces driving torque compared to standard thread profiles. This means your drill or driver does less work per screw, allowing you to drive more fasteners on a single battery charge - a practical advantage on large decking, dock, or boardwalk installations.

Is Type 305 stainless steel suitable for coastal or seaside environments?

Type 305 stainless steel provides strong corrosion resistance for outdoor, exposed, and moisture-prone environments such as residential decks, docks, and boardwalks. For seaside and coastal environments with direct saltwater exposure, a higher-grade stainless steel such as Type 316 is recommended for maximum protection.

What T-drive bit size does this screw require?

This screw uses a T20 6-lobe drive. The 6-lobe interface provides a secure, snug fit between the bit and the screw head, which helps prevent cam-out during driving and extends the working life of your driver bit - especially important when driving large quantities of screws in decking or dock construction.

Note: Product dimensions and/or thread length may differ from picture.