Metric Plastic Striaght Bulkhead Fitting Hose Barb Connector Inch Tube Adapter

The format is Barb OD – Thread Size – Barb OD (With Nuts). For example, "4-M6-4" means both barbs are 4 mm in outer diameter and the panel thread is M6. "Half 4-M6" means only one barb end is present (single-sided), with an M6 panel thread.

For a secure push-fit grip, choose flexible tubing whose inner diameter (ID) is approximately equal to or slightly smaller than the barb OD. For example, a 4 mm barb pairs well with 4 mm ID silicone or PVC tubing. Avoid tubing with an ID more than 1 mm larger than the barb OD, as this may result in a loose fit.

The usable thread engagement length varies by size. As a general guide, these fittings work with panels typically 1–5 mm thick. For thicker panels, check that the threaded shank length exceeds the panel thickness before ordering. Contact us if you need specific shank length data for a given size.

These connectors are designed for low-pressure applications. They can be used with compressed air at low pressures (typically under 0.5 MPa / 72 psi), but the exact rating depends on the specific size and tubing used. For higher-pressure pneumatic systems, we recommend verifying the working pressure with us before use.

The plastic material is compatible with water, mild aqueous solutions, and air. Compatibility with solvents, fuels, or aggressive chemicals depends on the specific plastic grade. If you plan to use these with anything other than water or air, please contact us to confirm chemical compatibility before ordering.

Full-through variants (e.g., "4-M6-4") have a hose barb on both sides of the panel fitting, allowing tubing to connect on each side. "Half" variants (e.g., "Half 4-M6") have a barb on one side only and a closed or flat face on the other — useful when you only need to route tubing through a panel from one direction, such as a tank inlet port.

For water applications, applying PTFE thread tape to the panel thread before tightening the nut is recommended to improve the seal. For air at very low pressures, a dry fit may be sufficient, but tape is still advisable for a more reliable seal. Do not over-tighten, as plastic threads can crack under excessive torque.