Flat Oval Spiral Duct Look at the beneath video to begin to see the installation of oval duct and fittings. Discover the reducer being used is undersized on its collar allowing for the oval duct to slide in excess of the collar. They may be applying Unistrut with threaded rods https://ovalconduit80122.liberty-blog.com/36766786/the-definitive-guide-to-oval-conduit