Flat Oval Spiral Duct Check out the underneath online video to see the set up of oval duct and fittings. Observe the reducer being used is undersized on its collar allowing for the oval duct to slip over the collar. They can be employing Unistrut with threaded rods as hangers https://ovalconduit80112.blog4youth.com/37236651/an-unbiased-view-of-round-conduit