A connection is provided whereby a first tube, which may be bent into an elbow, has at least one end flow drilled. A first one of the sensor elements has a first angular separation relative to the center point from a second, adjacent sensor element and a second angular separation relative to the center point from a third, adjacent sensor element. A heater section at least partially surrounds the inner electrical conductor. The display unit electrically connected to the control chip displays a voltage value of the feedback voltage according to the display information. The non-electric-power generating part includes a hydrophilic part near an outlet of the fluid passage of the reaction gas, and a hydrophobic layer formed on the hydrophilic part and exposed to the fluid passage to discharge water generated in generating an electric power. Should the user hear something interesting in the conference call, or if the user hears someone ask a question directed to the particular use, the user can switch back to the conference call.