Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4497205.

This adapter allows the stock, 6-inch hose to attach to a sheet metal duct in the same way the included window adapter attaches. I designed this to connect to an exhaust vent built into the side of my house, but it should also be useful for mounting to ceiling tiles, walls, etc.

I've included the native IPT file in case you need to add screw holes or other mounting hardware to the design.