#4 AN Plug

The #4 AN Plug from FRAGOLA is a hex head aluminum fitting designed to seal and close AN (Army-Navy) line ports in hydraulic, fuel, and fluid transfer systems. This compact plug is essential for technicians, fabricators, and enthusiasts building custom fuel systems, brake lines, or cooling circuits where temporary or permanent port closure is required. The #4 AN specification ensures compatibility with standard AN hose and fitting ecosystems used across automotive, motorsports, and industrial applications.

Machined from lightweight aluminum and finished in blue anodizing, the #4 AN Plug combines corrosion resistance with minimal weight addition to any system. The hex head design provides secure grip and torque application during installation and removal, preventing rounding and allowing for reliable, repeatable servicing. Blue anodizing protects the aluminum from oxidation and fluid exposure while maintaining the professional appearance required in show-quality or high-performance builds. At just 0.02 lbs, the plug's minimal mass makes it ideal for weight-conscious applications where every fraction matters.

This fitting suits anyone performing system diagnostics, modifications, or upgrades on custom fuel systems, cooling circuits, or hydraulic assemblies. Whether capping off an unused port during a fuel injection retrofit or sealing lines during troubleshooting, the #4 AN Plug delivers the dependability expected from FRAGOLA's engineered fittings. Proper installation with appropriate torque specifications ensures a leak-free seal; users should verify compatibility with their specific AN line size and fluid type before assembly.