Modular filing system expands with your needs. Start with a Top and Base Unit, then add as many Filing Tiers as needed. Easy to install and expand; add another level simply by removing the top and stacking on another tier. Heavy-duty, reinforced steel shelves hold letter size files or folders. Sturdy steel dividers, four per shelf, are welded between frame and shelf for stability; rolled edges for safety and embossed structural ribs for strength. Creates flexible expandable shelving. Order one unit for each stack of tiers.