The screws are using self tapping specially hardened steel screw, W-Cut thread design as zip tip, climatek coated, sharp threads and points to built in washer for interior or exterior use in carrying beams, ledger boards, stair rails, deck posts, playground equipment and other professional applications. Zip-Tip - Eliminates predrilling and one step installationUnique Thread Design & Washer Style Head- Unique thread design draws two substrates together while washer head allows zero gap jointsW-Cut - Low installation torque allows for fast driving and ease of installCEE Thread -Enlarges hole to reduce splitting, thus eliminating reworkESR-2442 Approved-Approved for structural applications