Solid Brass Compression Union Assortment

The 4LifetimeLines® Solid Brass Compression Union Assortment equips you with the hardware needed to join 3/16″, 1/4″, and 5/16″ tubing in low-pressure systems—air, oil, water, and transmission cooler lines. Each fitting is machined from dezincification-resistant brass to resist corrosion and provide a metal-to-metal seal without flaring tools or sealant. Housed in a durable, labeled tackle-box, this kit ensures you always have the right union on hand for emergency repairs or permanent installs.

What’s Included

2 x 1/8" Brass Compression Union

10 × 3/16″ Brass Compression Unions

4 × 5/16″ Brass Compression Unions

2 x 3/8" Compression Unions

2 x 10mm Brass Compression Unions

1 Compartmentalized organizer for neat storage and quick selection

Key Benefits

Corrosion-Resistant Brass: Dezincification-proof alloy stands up to moisture and chemicals.

Tool-Free Sealing: Compression sleeves bite into tubing for a leak-proof joint—no thread-seal tape required.

Universal SAE Sizes: Covers the three most common low-pressure tube diameters for versatile use.

Ready-to-Use Kit: Organized tackle-box keeps fittings and sleeves sorted and accessible.

Lifetime Warranty: Built to last—and backed for life by 4LifetimeLines®.

Ideal Applications

Use these brass compression unions in any low-pressure fluid line up to 500 PSI, including:

Air compressor and pneumatic tool connections

Oil cooler and transmission cooler return lines

Water and coolant plumbing in marine or industrial equipment

Fuel‐return circuits (non-high-pressure feed lines)

Not for use on automotive brake systems.

How to Use

Cut & Deburr: Trim tubing squarely and remove sharp edges.

Assemble Sleeve & Nut: Slide the compression sleeve onto the tube, then thread on the union nut.

Torque to Seal: Tighten the nut to the specified torque—the sleeve compresses around the tube for a permanent seal.

Inspect & Test: Pressurize the system and check for leaks before full operation.