Flat Oval Spiral Duct Enjoy the below movie to begin to see the set up of oval duct and fittings. See the reducer being used is undersized on its collar making it possible for the oval duct to slip above the collar. They're using Unistrut with threaded rods as hangers https://rylanbsgvi.laowaiblog.com/35499348/new-step-by-step-map-for-round-conduit