Stainless steel 18-8 coupling nuts

A Stainless Steel 18-8 Coupling Nut is a high-quality, durable fastener that offers greater corrosion resistance than HDG or zinc alternatives, often used in marine, chemical-exposure, and moisture-heavy 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 easy tightening with standard wrenches and sockets, and the stainless steel construction provides reliable performance in corrosive, moisture-heavy environments while maintaining a clean, polished appearance.