Flat Oval Spiral Duct View the beneath online video to begin to see the set up of oval duct and fittings. Observe that the reducer getting used is undersized on its collar enabling the oval duct to slide more than the collar. They're working with Unistrut with threaded rods as https://ovalconduit52344.kylieblog.com/37279602/top-latest-five-oval-conduit-urban-news