Homeowner building his own home. Did the main electrical and water heaters also. He didn't do too bad however, the electrical could have been a bit nicer. The coffee can is catching the drip from his gauge that was hand tight . Oh well, really nice people and they did a nice job on the home (they still have a ways to go). Stopped in to light off the hot water assist and all is working very well.
No, it's not duct board, just well insulated metal