Couplings slip inside the ends of two round ducts for being joined jointly after which you can sheet metal screws are fastened to hold it in place. Couplings could possibly be essential at a specific dimensions such as connections 18” and bigger. The shaded place during the graphic below will https://knoxslbpd.newsbloger.com/37325815/5-tips-about-round-conduit-you-can-use-today