Valved couplers and gas processing components particularly suitable for ultra-high purity gas distribution for use in semiconductor manufacturing. In the couplers, a valve stem/bullnose seals the aperture of the coupler immediately adjacent the exterior of the coupler, so that only a minimal amount of the wetted surface of the coupler is exposed to the external environment. A gas processing component (e.g., a filter), or an entire integrated gas stick assembly, may be sealed from the exterior environment at both its inlet and outlet sides, by these valved couplers. As a result, the entire device can be purged after manufacture and left in a controlled environment during shipment and installation, reducing the need for purging after installation.