Structural F23 Multi-Purpose Flat Head Wood Screws 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. Warning: This product can expose you to chemicals which is [are] known to the State of California to cause cancer and birth defects or other reproductive harm.