Large enough to safely store hat boxes and saddle pads up off the floor. Our Flat Shelf is meant for the top tier of the Main Frame, however it will also fit onto our Rolling Dolly. Some folks take our Main Frame and add 4 Flat Shelves for additional storage. It is made from 3/8" and 1/8" diameter basic steel & then zinc plated or powder coated to guard against rust & corrosion. It measures 28"W X 26"D.