#6 x 9/16-18 (#6) Radius O-Ring Fitting

The #6 x 9/16-18 (#6) Radius O-Ring Fitting by FRAGOLA is a precision hydraulic and pneumatic adapter engineered for high-pressure fluid transfer systems. This straight male-to-male o-ring fitting connects two identical #6 AN (Army-Navy) ports, making it essential for fuel injection, brake lines, coolant loops, and performance tuning applications where leak-free connections are non-negotiable. Whether you're building a custom racing fuel system, restoring a classic vehicle, or upgrading industrial hydraulic equipment, this fitting ensures secure, vibration-resistant connections under demanding operating conditions.

Constructed from lightweight aluminum and finished in blue anodize, this adapter combines durability with corrosion resistance while minimizing weight in performance-critical applications. The radius o-ring design creates a metal-to-metal seal when the o-ring is compressed between the fitting body and mating port, eliminating reliance on thread sealant and reducing the risk of leaks at vibration-prone connection points. The 9/16-18 thread specification ensures compatibility with standard #6 AN ports while the straight geometry allows direct port-to-port coupling without any flow path restrictions, maintaining optimal system pressure and flow characteristics.

Professional mechanics, hot rod builders, and automotive engineers rely on FRAGOLA fittings for their proven track record in high-vibration and high-pressure environments. This fitting is ideal for adapting fuel systems, coolant lines, or brake circuits where two matching #6 AN male connections require a straight adapter. Installation is straightforward—simply hand-tighten the fitting until the o-ring seats, then use a wrench to snug it an additional quarter-turn to ensure proper seal. Compatible with all standard #6 AN hose and tubing assemblies, this single fitting is a cost-effective solution for system modifications, repairs, or custom builds.