Female to Male Expander Adapter; Female -4 to -6

The VIBRANT PERFORMANCE Female to Male Expander Adapter (4 AN Female to 6 AN Male) is a straight-flow AN fitting designed to seamlessly integrate smaller diameter hose lines into larger diameter system ports without flow restriction or leakage. Machined from aluminum and finished in black anodized coating for corrosion resistance, this adapter maintains full structural integrity under high-pressure hydraulic and fuel system applications common in performance vehicles, racing platforms, and custom builds.

The 4 AN to 6 AN step-up design allows technicians to transition from smaller-gauge hose assemblies to larger ports while preserving system pressure and flow characteristics. AN (Army-Navy) sizing standardizes hose and fitting compatibility across automotive, aerospace, and marine industries—4 AN equals 1/4-inch nominal ID, while 6 AN equals 3/8-inch nominal ID. The straight configuration eliminates directional constraints, enabling flexible routing in confined engine bays or fuel cell compartments. Black anodizing provides durable surface protection against fuel, coolant, and salt air exposure without compromising aluminum's lightweight properties or adding measurable weight.

This adapter suits builders upgrading fuel system capacity, transitioning brake lines to larger-diameter assemblies, or consolidating multi-hose bundles through single larger-bore ports. It is essential for custom fuel injection installations, high-flow cooling systems, and performance suspension builds where line diameter transitions are unavoidable. VIBRANT PERFORMANCE AN fittings are engineered to SAE J518 standards, ensuring thread pitch, port sizing, and sealing surfaces meet OEM specifications for leak-free operation at sustained pressures.