A system for on-stream sampling of pressurized process gas such as natural gas or the like, said system optimized for use with pressurized process gas having liquid entrained therein, or otherwise referenced as “wet”. In the preferred embodiment, the probe tip is situated laterally from one side of the inner pipe wall to the other so as to span the entire inner diameter (ID) of the pipe, the probe tip having formed along its outer surface sample collection slot along the length of said outer surface, providing a “linear sample” of the fluid flow of the entire breadth of the flow, providing an accurate sample of even disassociated flow with entrained liquid particles and flow. Embodiments for continuous sampling, batch mode, spot sampling are provided, as well as an anti-vibration feature.