The Double-Sided Solid Aluminum Shelf mounts on 19-in. open frame rack. It consists of two shelves mounted on each side of the open-frame rack to form a double-sided shelf. It is a lighter weight solution compared to the steel version. This system uses 4U rack space and the maximum load rating is 100 lb. (45.4 kg) per side, 200 lb. (90.7 kg) total.