CheeMuii DOT Air Line Quick-Connect Straight Union Kit — 30PC (10×1/4, 10×3/8, 10×1/2) Brass Push-to-Connect

CheeMuii 30PCS Brass DOT Air Line Fittings are a complete quick-connect union kit for DOT-compliant air brake and pneumatic lines, available in 1/4", 3/8" and 1/2" sizes.

This compact kit supplies 30 DOT-style straight union fittings manufactured from CA360 brass with high-strength plastic components. Built to meet DOT FMVSS 571.106 and SAE J1131 considerations, these unions are engineered for corrosion resistance, temperature resilience, and straightforward push-to-connect assembly. They’re intended for repairing or assembling air brake tubing, air suspension lines, and general pneumatic connections on trucks, RVs, and industrial equipment.

How do these fittings simplify air line repairs?

The quick-connect straight union design removes the need for complicated tools or soldering when joining two sections of DOT tubing. A simple push-in action locks the tubing in place and creates a serviceable union for pneumatic systems.

• Push-to-connect mechanism for fast assembly
• Includes ten 1/4", ten 3/8" and ten 1/2" unions for common hose sizes
• Reusable unions that allow disconnection when needed
• No special crimpers or heat required for installation

What performance limits and environmental ranges do these unions support?

The brass and plastic blend in these fittings tolerate a wide operational envelope suitable for many vehicle and shop environments. They function from vacuum up to 500 PSI and hold up in temperatures from -30°F to +180°F (-34°C to +82°C), though tubing manufacturer limits should always be checked.

• Working pressure range: vacuum to 500 PSI
• Temperature range: -30°F to +180°F (-34°C to +82°C)
• Constructed from CA360 brass for corrosion resistance
• Designed to meet DOT and SAE air brake standards

Which applications are these DOT quick-connect unions suited for?

They’re tailored for air brake systems and other pneumatic lines found on heavy vehicles, trailers, and workshop equipment. The unions work with copper and DOT-spec tubing used in air suspension, brake lines, and general compressed-air plumbing.

• Truck and RV air brake repairs and maintenance
• Air suspension line joins and replacements
• Industrial compressed-air connections and hose repairs
• Towing equipment and workshop pneumatics

What’s included in the 30-piece kit and how is it packaged?

The kit contains three sizes of straight union fittings—ten of each size—selected to cover most common DOT tubing diameters. Packaging keeps the pieces grouped so you can grab the right size for on-the-road fixes or bench repairs.

• 10 × 1/4" DOT straight unions
• 10 × 3/8" DOT straight unions
• 10 × 1/2" DOT straight unions
• Compact set suitable for toolbox or service kit storage

Who is this for: This CheeMuii 30PCS DOT Brass DOT Air Line Fittings kit is made for mechanics, fleet technicians, RV owners, and do-it-yourselfers who need reliable, standards-compliant unions for air brake and pneumatic tubing. It’s useful for emergency roadside repairs, scheduled maintenance, and shop installations where DOT-spec components and quick, tool-free connections are preferred. Verify tubing compatibility and manufacturer limits before use to ensure correct pressure and temperature handling for your specific system.