#4 x 3/4-16 (#8) Radius O-Ring Fitting Black

The #4 x 3/4-16 (#8) Radius O-Ring Fitting Black from FRAGOLA is a precision hydraulic and pneumatic adapter designed for high-reliability applications where fluid transfer integrity is non-negotiable. This straight AN fitting converts between #4 AN male threads and #8 AN male O-ring ports, making it an essential component in fuel systems, brake lines, custom plumbing, and performance vehicle builds. Whether you're assembling a race car fuel system, rebuilding a vintage aircraft hydraulic line, or upgrading industrial equipment, this adapter ensures leak-free connections under pressure and vibration.

Constructed from aluminum and finished in black anodized coating, the #4 x 3/4-16 (#8) Radius O-Ring Fitting Black delivers corrosion resistance and durability in demanding environments. The radius O-ring design creates a metal-to-metal seal that is more robust than standard port designs, reducing risk of leakage during pressure spikes or thermal cycling. The straight configuration allows for compact in-line installation where space efficiency matters, and the #4 male thread size pairs with the larger #8 O-ring port for stepped flow applications or adapter bridge scenarios. FRAGOLA's precision manufacturing ensures thread concentricity and port finish meet aerospace-grade standards.

This fitting serves motorsports enthusiasts, industrial maintenance teams, and custom fabricators who demand reliability where system failure is costly or dangerous. It's ideal for retrofitting existing AN-threaded systems, constructing modular fuel or coolant loops, or bridging incompatible port sizes on components. Installation requires standard wrenches and basic hydraulic assembly knowledge; ensure proper torque application and use thread sealant compatible with your fluid type. The compact 1.4 x 1.25 x 4.1-inch footprint and lightweight 0.05-pound profile make integration straightforward in engine bays, chassis tunnels, or equipment cabinets where weight and clearance are factors.