The LedgerLOK Flat Head - Bucket of 250 install flush to ledger for easier joist hanger placement. LedgerLOK Flat Head Structural Wood Screws also include a TORX ttap drive system to ensure a smooth and wobble-free installation. LedgerLOK code-compliant structural wood screws are engineered to fasten a deck ledger board to the rim joist of a house with no predrilling. LedgerLOK replaces lag screws and through-bolts, has been coated with a proprietary three-step coating process that protects against corrosion (even in pressure treated wood) and is ACQ approved. The built-in washer head eliminates the need for an additional washer, saving time and money. Use the 5" for double ledgers and thicker applications.