#3 Female x #4 Male Swivel Expander Black

The #3 Female x #4 Male Swivel Expander Black by FRAGOLA is a precision AN fitting adapter engineered for high-performance fuel, coolant, and hydraulic line systems in modified vehicles and race applications. This straight adapter bridges two different AN port sizes while maintaining the integrity of your fuel system or cooling circuit, making it indispensable for custom engine builds, turbo installations, and fuel injection upgrades where existing line diameters must transition between components.

Constructed from aerospace-grade aluminum with black anodized finish, the #3 Female x #4 Male Swivel Expander features full 360-degree swivel capability on the female end, allowing flexible hose routing without kinks or stress on neighboring connections—critical when space is tight in engine bays. The male end threads directly into #4 AN ports, while the female swivel accepts standard #3 AN hose fittings, ensuring leak-free pressure-rated connections up to system limits. FRAGOLA's precise machining guarantees concentricity and sealing surface integrity, eliminating micro-leaks that compromise performance and reliability.

Mechanics and engine builders rely on the #3 Female x #4 Male Swivel Expander when adapting fuel rails, remote oil coolers, turbo feed lines, or coolant bypass passages during LS swaps, forced induction conversions, and vintage restorations with modern fuel systems. The swivel design prevents hose fatigue and vibration-induced failure in high-RPM applications, while the black anodized aluminum resists corrosion in underhood and engine-bay environments. Installation is straightforward—thread the male end into the larger #4 AN port and connect your #3 AN hose to the swivel female end using standard AN hose clamps or compression fittings.