Simpson Strong-Tie connectors make projects easier to build while making them stronger and safer, engineered and tested to perform and manufactured to the highest quality standards. The HDU is designed for use in shearwalls and braced-wall panels, as well as other lateral applications in wood construction. The HDU uses Strong-Drive® SDS Heavy-Duty Connector screws (not included) which install easily, reduce fastener slip and provide a greater net section than bolts. HDU 13-3/16 in. Hot-Dip Galvanized Predeflected Holdown (Pack of 432).