Rectus 21 Compatible Couplings
Looking for a Rectus® 21 Series compatible quick release coupling or plug?
This guide explains the recommended Kee Connections replacement, compatibility considerations and the available product configurations.
What is the Rectus 21 Series?
The Rectus 21 Series is a compact single shut-off quick release coupling profile with a 2.5 mm nominal bore, designed for low-pressure industrial applications involving compatible liquid and gaseous media. Its compact dimensions and automatic locking mechanism make it well suited to applications where installation space is limited and reliable connection performance is required.
The profile has been widely used by OEMs and maintenance engineers across industrial automation, instrumentation, laboratory equipment, medical devices and specialist pneumatic systems. Over many years it has become an established connection profile, meaning compatible couplings and plugs are often required when servicing, maintaining or upgrading existing equipment.
When replacing components within an existing system, it is important to confirm the connection profile, valve configuration, connection type, operating pressure and media compatibility before selecting a suitable replacement. This guide identifies the recommended Kee Connections series for applications requiring compatibility with the Rectus 21 Series connection profile.
Recommended Kee Series
050 Series | Single Shut Off Quick Release Couplings & Plugs
Mini industrial coupling, the world's most commonly used profile. Above average flow performance for liquid and gaseous media. Large bandwidth in materials and valve variants.
Compatibility Overview
The Kee 050 Series is designed as a compatible alternative to Rectus 21 couplings, providing a reliable solution for a wide range of industrial pneumatic applications.
The Kee 050 Series uses the same plug profile as the Rectus 21 Series, allowing interchangeability with compatible couplings and plugs already installed within existing systems. Comparable body sizes, connection formats, and flow characteristics make the 050 series the ideal choice for compressed air distribution systems where Rectus 21 compatibility is required.
Manufactured for dependable day-to-day industrial use, the Kee 050 Series offers a practical equivalent solution without requiring changes to existing mating connections or pneumatic layouts.
| Competitor Series | Recommended Kee Series | Compatibility |
|---|---|---|
| Rectus 21 Series | Kee 050 Series | Direct profile compatibility |
The Kee 050 Series provides the recommended replacement profile for Rectus 21 Series applications. Always confirm the application, thread connection and media before replacement.
Available Configurations
View the complete Kee 050 Series for specifications, dimensions and available configurations.
| Couplings | Available Sizes |
|---|---|
| Male Thread | 1/8", 1/4", 3/8", M10 x 1, M12 x 1.5, M14 x 1.5 |
| Female Thread | 1/8", 1/4", 3/8", M10 x 1, M12 x 1.5, M14 x 1.5 |
| Hosetail | 4 mm to 10 mm |
| Tube Connection | 4 × 6 mm to 6 × 8 mm |
| Bulkhead Hosetail | 4 mm to 10 mm |
| Bulkhead Tube Connection | 4 × 6 mm to 6 × 8 mm |
| Spring Guarded Tube Connection | 4 × 6 mm to 6 × 8 mm |
| Plugs | Available Sizes |
|---|---|
| Male Thread | 1/8", 1/4", 3/8", M10 x 1, M12 x 1.5, M14 x 1.5 |
| Female Thread | 1/8", 1/4", 3/8", M10 x 1, M12 x 1.5, M14 x 1.5 |
| Hosetail | 4 mm to 10 mm |
| Tube Connection | 3 × 5 mm to 6 × 8 mm |
| Bulkhead Hosetail | 4 mm to 10 mm |
| Bulkhead Tube Connection | 4 × 6 mm to 6 × 8 mm |
| Spring Guarded Tube Connection | 4 × 6 mm to 6 × 8 mm |
Technical Compatibility
The Rectus 21 Series and Kee 050 Series are compact single shut-off quick release coupling profiles intended for compressed air and pneumatic applications.
When selecting a replacement, consideration should be given to:
- Connection profile compatibility.
- Valve configuration.
- Thread or hose connection.
- Operating pressure.
- Temperature requirements.
- Media compatibility.
Where compatibility has been confirmed, the Kee 050 Series provides a practical replacement solution with a wide choice of connection options.
Typical Applications
This profile is commonly found within:
- Industrial compressed air systems
- Automation equipment
- Pneumatic control systems
- Manufacturing machinery
- OEM equipment
- Maintenance and repair applications
Advantages of the Kee Replacement
Kee Connections supplies a comprehensive range of quick release couplings and plugs suitable for industrial pneumatic systems.
Benefits include:
- Extensive range of coupling and plug configurations.
- Multiple thread and hose connection options.
- UK technical support.
- OEM and maintenance supply.
- Complete hose assembly capability.
FAQs
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