Single/ Twin Pipeline Adaptor allows plugging of oxygen flow meter and probes from front and bears weight of the metal BPC flow meter and humidifier. The Adaptor can be pushed to insert and press-to-release mechanism for flow meters and probes and locating terminal unit pin and probe notch gives maximum stability to the flow meter unit. The Adaptor has the feature that safety key plug used with schrader type self sealing valves can also be used on the terminal units so that existing ancillary equipment can be inserted in both the terminal units as well as schrader type sealing valves. The Single/ Twin Pipeline Adaptor has non interchange ability between probes and terminal outlets for different services.