#4 AN Plug Black

The #4 AN Plug Black from FRAGOLA is a precision hydraulic and pneumatic fitting designed for high-performance fluid systems in automotive, aerospace, and industrial applications. This aluminum plug delivers a secure dead-end closure for AN (Army-Navy) standard lines, preventing fluid leakage and maintaining system integrity under demanding conditions. Built for professionals and enthusiasts who demand reliability in fuel, oil, coolant, and brake line assemblies, the #4 AN Plug Black is an essential component for custom hydraulic builds and motorsport fuel systems.

Constructed from lightweight aluminum and finished in black anodized coating, this plug resists corrosion and oxidation while maintaining a professional appearance in engine bays and fuel cell installations. The hex head design allows for secure installation and removal using standard wrenches, ensuring consistent torque application without stripped threads. The #4 AN specification corresponds to a 1/4-inch line diameter, making it compatible with quarter-inch hydraulic hose assemblies commonly used in performance fuel systems, cooling circuits, and custom plumbing applications. Black anodizing provides both aesthetic appeal and protective durability against fuel, oils, and ambient moisture exposure.

This fitting is ideal for fabricators, race teams, and hot rod builders who need reliable AN line termination components for fuel injection systems, nitrous oxide systems, and oil cooler circuits. Installation requires standard AN hose fittings or tubing adapters on mating lines; the plug threads directly into #4 AN female ports. Whether capping unused fuel rail ports, blocking coolant line dead ends, or securing custom hydraulic circuits, the #4 AN Plug Black delivers leak-free performance at a compact size (1.2 x 1.05 x 4.1 inches) and minimal weight (0.02 lbs). FRAGOLA's reputation for precision engineering ensures this plug meets OEM standards for pressure-rated fluid systems.