Coilhose Pneumatics 591 Pneumatic Coupler 3/8 Npt

Product Description

The COILHOSE PNEUMATICS 591 is a male NPT pneumatic hose coupler designed for compressed air tool connections in shop and field environments. Built from nickel-plated steel, it accepts a 3/8-inch male NPT threaded connection and features a 3/8-inch body diameter. It is rated for a maximum working pressure of 300 psi and operates across a temperature range of -40 to 250 degrees F. This coupler follows the Tru-Flate Automotive interchange standard, making it a direct-fit replacement for existing Tru-Flate-compatible setups. Installation is handled by HVAC technicians, automotive shop mechanics, and general maintenance trades working with compressed air systems.

This coupler is suited for residential garages, automotive service bays, and light industrial compressed air distribution lines. It connects air tools, blow guns, inflators, and other pneumatic accessories to standard shop air hose assemblies. The Tru-Flate Automotive interchange profile is widely used in automotive service environments across North America, making this coupler a common replacement or expansion fitting for existing pneumatic hose systems.

Key Features

• Tru-Flate Automotive interchange standard for broad shop compatibility
• 3/8-inch MNPT threaded connection for secure, leak-resistant attachment
• Nickel-plated steel construction for corrosion resistance and durability
• 300 psi maximum working pressure rating
• Wide operating temperature range: -40 to 250 degrees F
• Compact 3/8-inch body diameter fits standard pneumatic hose assemblies

Compatibility

Designed as an OEM-style replacement or add-on coupler for pneumatic hose systems using the Tru-Flate Automotive interchange standard with 3/8-inch NPT male threaded connections.

Installation Notes

This coupler is installed by qualified maintenance technicians or mechanics working on compressed air systems. Depressurize and bleed the air line completely before disconnecting or installing any pneumatic fittings. Use thread sealant or PTFE tape on the NPT threads and tighten with an appropriately sized wrench — do not overtighten steel fittings into aluminum manifolds. Verify all connections hold pressure before returning the system to service.