External Thread Straight Joint Plastic Tube Connector 4mm–25mm

Measure the outer diameter (OD) of your tube — not the inner diameter. Use a caliper or ruler across the widest point of the tube end. Match that measurement to the Size(mm) option (e.g., if your tube OD is 10mm, select the 10mm variant). Also confirm whether your fitting port uses a 1/2" or 3/4" thread before ordering.

The thread size refers to the external (male) thread on the connector body that screws into a female-threaded port or coupling. 1/2" and 3/4" are nominal pipe thread sizes — they do not directly equal the tube OD. Check the thread specification of your existing fitting or manifold port to select the correct thread size.

These plastic connectors are suitable for low-to-moderate pressure air and water applications typical of DIY and light workshop use. For high-pressure pneumatic systems (above approximately 8–10 bar / 116–145 psi), a metal fitting is generally recommended. Always test at low pressure first and inspect for leaks before full operation.

For water or air lines where a leak-free seal is required, wrapping the external threads with 2–3 layers of PTFE (plumber's) tape before assembly is recommended. This fills minor thread gaps and helps prevent weeping joints, especially in pressurized systems.

The tube OD sizes listed (4–25mm) are metric measurements. If you are working with imperial tubing, convert your tube OD to millimeters (e.g., 3/8" ≈ 9.5mm, 1/2" ≈ 12.7mm) and select the closest available size. A slight mismatch in OD may affect seal quality, so confirm the fit before pressurizing the line.

Yes. The plastic construction is corrosion-resistant and suitable for freshwater aquarium and pond recirculation lines. These connectors work well with standard aquarium tubing ODs. Avoid use with saltwater or aggressive chemical solutions unless the specific plastic grade is confirmed compatible.

For a small drip-irrigation setup with 5–10 connection points, a 10-piece pack provides enough connectors with a few spares. Larger garden or greenhouse installations with 20+ connection points benefit from the 20- or 30-piece packs, which also offer a lower per-unit cost.