Remote vent for a diesel heater fuel tank cap

While this might be product-specific (Vevor 2500W diesel heater), it should work with other fuel tanks. The stock fuel cap is vented by means of a simple pinhole, which means that any enclosed space that contains the fuel tanks sooner or later starts to smell of diesel fuel.

This part simply fits on top of existing fuel cap just to provide a convenient location to attach fuel line (for venting) that it then can be routed somewhere outside.