Was wondering about these windows. They look like a metal frame. Also I have wondered for many years how you get a good water seal when punching through corrugated steel. Seems like water entry would always be a risk.
aluminum windows. Water entry is not a risk at all. They come with a 1" nail fin (flange) that can be water sealed with window tape. The tape covers the nail flange, the sheathing and building paper. 100% waterproof.