12AN FM to FM Flare Swivel Coupling Black

The 12AN FM to FM Flare Swivel Coupling Black from REDHORSE PERFORMANCE is a precision-engineered hydraulic fitting designed for high-pressure fuel, oil, and coolant line applications in modified vehicles and performance engines. This coupling serves as a critical connection point in custom fuel systems, turbocharger setups, and engine bay plumbing where vibration isolation and leak-free reliability are non-negotiable. Built for serious enthusiasts who demand OEM-quality performance from aftermarket systems, this fitting bridges two female AN ports with a swivel design that accommodates minor misalignment without compromising seal integrity.

The 12 AN size designation indicates a nominal bore of 0.75 inches and rated for flows and pressures typical of fuel injection, coolant circulation, and power steering applications in turbocharged or supercharged engines. The FM-to-FM (female-to-female) configuration allows connection of two male AN-threaded line ends, while the flare swivel joint rotates 360 degrees to relieve installation stress and vibration-induced fatigue on brittle hoses and rigid lines. Black anodized aluminum construction resists corrosion and thermal cycling common in engine compartments, and the swivel design means you can install tight-radius line runs without kinking or twisting hoses that would otherwise fail prematurely.

This coupling is essential for builders transitioning between factory and custom fuel rails, intercooler piping, or brake fluid circuits where standard straight fittings introduce installation bind. Installation requires AN-compatible wrenches (typically 1-3/16 inch across flats) and hand-torque to manufacturer specs—over-tightening flare nuts risks cracking the aluminum body. Verify line-end threading (37-degree JIC flare) and pressure ratings before purchase, as this fitting is engineered for motorsport-grade systems and will not function in mismatched AN or SAE adapter arrangements.