Replace lag screws with the Grip Rite PrimeGuard Plus Hex Washer Head Structural Screw. The 5/16" x 4" screw drives with a 3/8" hex driver or a T-25 star bit (dual-drive head), and the Type 17 self-drilling point cuts into framing lumber without pre-drilling. PrimeGuard Plus exterior coating is approved for use in ACQ pressure-treated lumber, and the screws are ICC-ES evaluated under ESR-3933 for code-compliant structural connections.

• Size: 5/16" x 4"
• Dual-drive head: 3/8" hex washer with T-25 star recess
• Type 17 self-drilling point - no pre-drilling required in softwood framing
• PrimeGuard Plus corrosion-resistant coating (approved for ACQ-treated lumber)
• ICC-ES evaluation report ESR-3933 for code-compliant load-bearing connections
• Designed to replace lag screws in wood-to-wood structural attachment
• Free driver bit included with every box
• Pack: 20 screws per box

Applications: Deck framing and ledger attachment, pergola and gazebo construction, multi-ply beam lamination, stair stringer attachment, playground structures, and general exterior wood-to-wood structural connections.

Tip: 5/16" x 4" replaces 5/16" lag screws on doubled 2x rim joists, deck post bases bolted through 4x4 posts, and ledger attachments through 2x sheathing into 2x band. The 4" length lands solidly inside a 4x4 post or a doubled 2x joist.