Abstract: An indicator device which can be attached to a standard oxygen flow meter is disclosed. The indicator device has a rod along which a pointer can be moved and locked into position. The pointer can be set at the oxygen flow level prescribed by the physician as indicated by the scale on the oxygen flow meter. If the oxygen flow level is changed or if oxygen is discontinued for any period of time, the attendant can then set the oxygen flow to the prescribed level by controlling the valve on the oxygen flow meter so that the float, which indicates oxygen flowing liters per minute is positioned opposite the position of the pointer. This prevents erroneous or improper setting of oxygen flow levels to patients after interruption or change of oxygen flow level, which can be dangerous and life threatening.