This 21" x 42" Galvanized Solid Flat Metro Shelf has uncoated, aluminum cast corners are best suited in areas where corrosion protection requirements are minimal. Solid shelves feature a 1/8" 'ship's edge' and can provide a barrier between shelves to contain and protect products from spillage, or when used as a bottom shelf it can protect products stored on the unit from contamination from the floor. Super Erecta shelves accept Metro's 1" diameter posts, and feature a split sleeve adjustment, making them easy to precisely position in 1" increments along the grooved and numbered posts.