Access doors are used in duct systems for many reasons. Entry is often required to facilitate duct cleaning, examine equipment, or to test, repair, or troubleshoot system components. Flush Mount design streamlines air flow in 1” lined duct. Flush Mount Access Doors provide an easy four step solution. Size and cut a hole in the duct wall. Peel the release paper from the foam gasketed access door frame. Press the frame into position. Insert one screw into each of the four pre-punched holes in the frame. Cam Only access doors are typically used in tight spaces where a hinge is not functional.