Description
The Fixed Elbow, 1/4″ Thread x 3/8″ Push Fit (John Guest) is a high-quality 90° push-to-connect fitting designed to connect 3/8″ OD tubing to a 1/4″ threaded port. Commonly used in reverse osmosis systems, water filtration setups, and beverage equipment, this fitting allows for quick, secure, and leak-free installation without tools.
Built with trusted John Guest push-fit technology, it’s ideal for applications where higher flow rates (3/8″ tubing) are required while still connecting to standard 1/4″ threaded ports.
Key Features
- Push-Fit Technology: Tool-free installation—simply push tubing into place
- 90° Elbow Design: Ideal for tight spaces and clean routing
- 3/8″ Tube x 1/4″ Thread: Allows transition from threaded ports to larger tubing
- Leak-Free Seal: EPDM O-ring ensures reliable, long-term performance
- High Flow Capability: 3/8″ tubing supports increased flow vs 1/4″ lines
- Durable Construction: Typically polypropylene or acetal body
- Lead-Free & NSF Certified: Safe for potable drinking water use
📌 John Guest fittings use a collet locking system that securely grips tubing and allows easy removal without tools
Compatibility
This 1/4″ thread x 3/8″ push-fit elbow is compatible with:
- Reverse osmosis systems (especially higher flow setups)
- Under-sink filtration systems
- Ice makers and refrigerator lines
- Coffee machines and beverage systems
- Water coolers and dispensers
Works with:
- 3/8″ OD polyethylene (PE) tubing
- PEX tubing
- Nylon or soft copper tubing
Specifications
- Product Type: Fixed elbow (90° push-fit x threaded)
- Tube Size: 3/8″ OD
- Thread Size: 1/4″ NPT male (standard)
- Material: Polypropylene or acetal
- Seal Material: EPDM O-ring
- Max Pressure: ~150 PSI (varies by material)
- Max Temperature: ~140°F (60°C)
- Certifications: NSF 51 & NSF 61
Applications
The 1/4″ x 3/8″ Fixed Elbow is ideal for:
- Connecting RO systems to higher flow tubing lines
- Transitioning from valves, housings, or manifolds to tubing
- Tight under-sink installations
- Beverage and coffee equipment setups
- Ice maker and fridge water connections
It is especially useful when:
- Upgrading from 1/4″ to 3/8″ tubing for better flow
- Reducing pressure drop in longer runs
Maintenance & Installation Tips
- Cut tubing clean and square before inserting
- Push tubing fully into the fitting for a proper seal
- Use PTFE (Teflon) tape on threaded connections
- Avoid overtightening into plastic ports
- To remove tubing, press the collet and pull out the tube
💡 These fittings are widely used because they offer fast installation, reliability, and consistent leak-free performance in water treatment systems.

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