When looking at the Coronation register pictures you may want to try and visualize it without the screen. The little holes can be distracting. However, when attached to a cold air return and placed in a duct opening the screen does an excellent job of preventing a person from seeing all the ugly metal duct work. Screens are a no cost option and can be easily removed with a screwdriver.
Coronation grilles are solid cast metal, your choice of bronze or aluminum. Bronze has three patinas offered, as well as a nickel plated finish. Aluminum has three painted finishes offered.