Sep 02, 2017 · The round sheet metal duct pipe, adjustable elbows and metal duct strap are installed in this update. This project is continued from How to Install Round Sheet Metal Duct – Part 2. Project Index. How to Install Round Sheet Metal Duct Introduction, flex duct problems, sheet metal duct design and material cost. Black AU Adjustable Hat - Front features AU interlocking in RY outlined in WH - Back features Spartans ... Front features AU interlocking in RY outlined in WH - Back ... 3 Way Registers Proseles PS3WW Steel Register can be used in Residential and Light Commercial applications and easily installs in either a sidewall or ceiling. Ideal for shallow duct installations, it is constructed of steel, and features a multi-shutter valve.