#4 x 1/4 MPT Straight Adapter Steel

The FRAGOLA #4 x 1/4 MPT Straight Adapter Steel (part #581605) is a precision hydraulic and pneumatic fitting designed to bridge 4 AN male connections to 1/4 inch NPT male ports. This straight adapter delivers reliable fluid transfer in high-pressure systems, automotive cooling circuits, fuel delivery applications, and industrial pneumatic setups where male-to-male port adaptation is required.

Constructed from steel with a zinc oxide protective coating, this fitting resists corrosion in harsh environments and maintains structural integrity under pressure cycling. The 4 AN (AN4) thread standard accommodates hoses and hard lines rated for medium-flow applications, while the 1/4 inch NPT (National Pipe Thread) side connects directly to standard industrial manifolds, gauges, and equipment ports. The straight configuration eliminates directional offset, simplifying installation in tight spaces and reducing pressure drop across the connection point.

This adapter is essential for technicians and engineers assembling custom hydraulic lines, restoring classic vehicles with modern cooling systems, configuring aftermarket fuel systems, or maintaining industrial equipment. The compact design (1.3 x 0.75 x 4.3 inches) fits within confined engine bays and equipment enclosures. Each unit arrives ready to install—no modifications or additional tooling required. The zinc oxide finish provides additional protection during storage and field use, ensuring long-term reliability without premature degradation.

FRAGOLA fittings are recognized for manufacturing precision adapters and hose assemblies that meet SAE and ISO standards. The #4 x 1/4 MPT adapter represents dependable engineering for systems where leakage, pressure loss, or connection failure cannot be tolerated. Stock this fitting as a critical component in your fluid systems toolkit or order as a replacement for existing male-to-male adapter connections.