Abstract: For use in measuring air velocity and pressure changes in a duct, a gauging system comprising a gauge including a vertically extending transparent tube within which a ball moves to a position corresponding to the pressure in the tube above and below the ball, a velocity scale and a pressure scale extending alongside the tube and increasing from their lower end to their upper end, a vertically extending transparent shell enclosing the tube, and one or more rigid tubes for connecting the lower end of the gauge tube to the interior of the duct to read total pressure or static pressure and a flexible tube for connecting the upper end of the shell to the interior of the duct to read static pressure.