Hot dipped galvanized (HDG) coupling nuts

A Hot-Dipped Galvanized (HDG) Coupling Nut is a heavy-duty fastener that offers superior corrosion resistance compared to zinc alternatives and is often used for exterior, structural, and high-moisture fastening applications.

These are sometimes called “coupler nuts” or “extension nuts”. Coupling nuts have a cylindrical body, a fully threaded interior, and open ends on each side, designed to join two externally threaded fasteners end to end. Their elongated hex body allows for easy tightening with standard wrenches and sockets, and the hot-dipped galvanized coating provides reliable performance in demanding outdoor and moisture-heavy environments.