Flat Oval Spiral Duct Look at the below movie to begin to see the installation of oval duct and fittings. Observe which the reducer being used is undersized on its collar allowing for the oval duct to slip in excess of the collar. They're employing Unistrut with threaded rods as https://ovalconduit68900.aboutyoublog.com/42722071/an-unbiased-view-of-oval-conduit