#4 Port Plug 7/16-20 Black

The #4 Port Plug 7/16-20 Black from FRAGOLA is a professional-grade hydraulic and pneumatic fitting designed for engineers, mechanics, and technicians who require reliable port sealing in fluid power systems. This compact aluminum plug serves as a critical component in manifold blocks, pressure lines, and custom fluid transfer applications where unused ports must be securely sealed to prevent contamination, pressure loss, and system failure. Whether you're building a custom hydraulic circuit, maintaining industrial equipment, or assembling aftermarket performance systems, this port plug delivers the dependable closure your application demands.

Engineered from black anodized aluminum, the #4 Port Plug features a 7/16-20 thread pitch that mates precisely with AN-standard port configurations, ensuring a leak-free fit without the need for additional adapters or workarounds. The hex head design allows for straightforward installation and removal using standard wrenches, while the integrated O-ring seal creates a positive barrier against fluid migration across the port interface. This O-ring design eliminates reliance on thread sealant tape, reducing assembly complexity and improving reliability in high-vibration or high-pressure environments where traditional tape sealing can fail.

Professionals in automotive fabrication, aircraft maintenance, agricultural equipment assembly, and industrial fluid power systems rely on this fitting for systems operating at both high pressure and temperature cycling. The black anodized finish resists corrosion in demanding shop environments, while the aluminum construction keeps weight to a minimum—critical in aerospace and motorsports applications where every ounce matters. Installation is straightforward: simply thread the plug into the unused port until hand-tight, then torque to specification using the hex head for wrench engagement. This single plug is sold individually, making it ideal for stockpiling spares or completing custom manifold builds without purchasing full kits.