Profile: On Line Controls, Inc. specializes in offering ultra low air pressure regulators and controllers for plastic tubing. Our microair provides precise control of tubing outside diameter by regulating air pressure to a set point during the manufacture and extrusion of tubing. Our MicroAir II ultra low air pressure regulators and controllers accepts air up and air down contact closure inputs from a diameter gauge or other controllers with up/down contact closures or logic outputs. Pressure is regulated by balancing against a low tension spring and by venting the surplus air.