The Simpson Strong-Tie SDS25312MB Strong-Drive SDS Heavy-Duty Connector Screw is a 1/4 in. x 3-1/2 in. structural wood screw sold in a 125-count pack. This is a heavy-duty connector screw designed for fastening Simpson Strong-Tie connectors and for structural wood-to-wood applications where you want strong holding power without the extra step of predrilling. Model Number: SDS25312MB.

What makes this screw matter on the job is how it goes in. The Type-17 point is there to start quickly and reduce splitting, so you can move faster in framing, deck work, and connector installation. The serrated threads help the screw pull and bite into the wood instead of just forcing its way through it, which gives you a tight connection with less fuss.

This fastener uses a 3/8 in. hex drive and a hex head with an integrated 0.500 in. washer. In practical terms, that means better driver engagement, less chance of cam-out, and better bearing surface under the head. That wider bearing area helps clamp hardware and wood securely, which is exactly what you want when working with heavy-duty connectors and structural assemblies.

The 3-1/2 in. overall length and 2-1/4 in. thread length put this specific SDS25312MB in a useful middle ground for many connector and exterior wood fastening jobs. It is long enough for serious engagement in wood, but still sized for applications where you do not want to jump all the way to the longer 4-1/2 in., 5 in., or 6 in. versions in the SDS line.

For outdoor use, the double-barrier coating is one of the big reasons to choose this version. It is intended to improve corrosion resistance versus plain steel fasteners, which matters in deck framing, exterior projects, and other jobs where moisture is part of the deal. If you are matching the fastener to exterior connector work, that coating is not a throwaway spec. It is part of the reason the assembly lasts.

Simpson Strong-Tie also designed these for easy identification after installation. The head is stamped with the Simpson Strong-Tie identification mark and the fastener length, which helps when you are inspecting completed work or verifying that the right screw went into the right connector location.

Installation is straightforward, but the recommended setup matters. Simpson Strong-Tie calls for a low-speed 1/2 in. drill with a 3/8 in. hex driver. That makes sense for a fastener in this size class because controlled speed and steady torque help the screw seat cleanly without burning up the driver or overdriving the connection.

Who is this for? Contractors, deck builders, remodelers, carpenters, and serious DIY users who need a structural wood screw for connector fastening and exterior wood work. If you are installing heavy-duty Simpson Strong-Tie connectors, or you want a stronger and faster alternative to old-school lag-style installation in many wood applications, this is the kind of fastener worth buying by the box instead of by the handful.

Simpson Strong-Tie SDS25312MB Strong-Drive SDS Heavy-Duty Connector Screw is the one you buy when you want structural bite without wasting time

This is a jobsite-friendly structural screw that cuts out extra steps, drives clean with a hex head, and makes a lot more sense than fighting with slower old-school fastening methods.

• Who it's for: Carpenters, deck builders, remodelers, and serious DIY users installing connectors or doing exterior wood fastening.
• Why it stands out: Type-17 point, serrated threads, integrated washer, and a corrosion-resistant double-barrier coating all work together to make installation faster and more reliable.
• Worth knowing: This is a 125-pack of screws, not a kit with extra accessories, so make sure you have the right 3/8 in. hex driver on hand before you start.

• Does this screw require predrilling? No. The Type-17 point is designed for easy driving without predrilling.
• What drive does it use? It uses a 3/8 in. hex drive.
• What is this screw mainly used for? It is intended for heavy-duty Simpson Strong-Tie connectors and structural wood applications, including exterior wood fastening.
• What comes in this package? This SDS25312MB package contains 125 screws.