Couplings slip Within the finishes of two round ducts for being joined collectively and afterwards sheet metallic screws are fastened to hold it in place. Couplings may be demanded at a specific size for example connections eighteen” and bigger. The shaded place in the graphic beneath would be the coupling. https://ovalconduit34455.blog-gold.com/48217103/5-simple-statements-about-oval-conduit-explained