What type of vent is required for a cooktop vent down and out an exterior wall (for the outside wall itself) I am installing an electric cooktop, with a pop-up downward vent...

I am installing an electric cooktop, with a pop-up downward vent that pulls steam and such through pipes contained by the floor, and out through a stucco exterior wall. What type of vent is required in that exterior wall?
Why does my AC verbs to blow nouns...
Answers:    A single-wall galvanize vent will do.

READ THE MANUAL!

Sorry for shouting, but it'll all be contained by there. It'll relate you the size, max distance, max number of elbows, etc.

Don't skimp by reducing the vent size - it may not work.