Repair outside vent covers for bath fan - takes 10 min (serviced 2022)

Replacing bathroom exhaust fan outside vent cover. Original vent cover was plastic and can last about 14 yrs. This showing a simple replacement process without having to pull the 4in duct out, which saves a lot of work.

[@yassin9249]

If I want to seal it what kind of caulk should I use please

[@kimswitzer9452]

Does that metal flap stay flapping?