Abstract: Work persons, wearing clear hoods supplied with breathable air, performing tasks in contaminated spaces, are provided with an in line personal airflow gage. The breathable air passing through the gage moves through an especially shaped volume or chamber, which centers on a variable curved interior surface of the underside portions of an inner indicia receiving cover of this personal airflow gage. How this surface is varied serves to initially calibrate this gage. Also initially and subsequently, this gage is calibrated by selecting a coiled spring, which provides the resisting and returning force of the airflow indicating arm or pointer. This arm in turn is coupled to a pivotal air blade, also called the flag, which partially rotates, pivots or deflects, within a one hundred and eighty degree range, back and forth within the especially shaped volume, through which the breathing air passes.