Structural F23 F23 Deck Ledger / Multipurpose Flat Head Wood Screw are designed for heavy duty framing applications such as decking, fencing, pergolas, landscape timbers, and timber framing. The 4" and 5" lengths are specifically designed as code compliant deck ledger attachments. The F23s are fully tested and code compliant alternatives to traditional lag screws and through-bolts, with no pre-drilling required. These versatile screws feature a low-profile flat head design that minimizes interference with connectors and finish materials, a unique Tri-Forge point for reduced driving torque, and a high-adhesion exterior grade coating.