Flat Oval Spiral Duct Observe the down below movie to begin to see the installation of oval duct and fittings. Observe that the reducer being used is undersized on its collar permitting the oval duct to slide more than the collar. They may be utilizing Unistrut with threaded rods as https://cristianizobq.blog-ezine.com/36810975/considerations-to-know-about-round-conduit