The CDRAMS was developed in response to industry requirements for a round air measuring damper with low leakage and easy to install in round spiral ductwork. The specially designed blade-to-frame polyethylene foam seal sandwiched between two round blades and fully encompasses the edge. The extruded aluminum airfoil sensing tubes sample the air pressure across the full diameter of the duct. The CDRAMS can be furnished with a variety manual, pneumatic, electric actuators (fail-safe spring return or double acting). The CDRAMS is available with controller, electric actuator factory calibrated.