Star Destroyer #3

[ringa]

I am making good progress on the main docking bay. It's taking a long time to scratch build most of what's in there. I'm very close to finishing it. This is one of those areas on the model I would like to be as accurate as possible.

In the screen cap below, I've outlined the part(s) I need to make the forward, double bay openings. Does anyone know what that is made from?

Thanks!