Tennsco Add-A-Stack Top/Base,Letter,no Levelers,36"x13-3/16"x4",SD Modular filing system expands as easily as adding another shelf. Thin profile reduces height of each tier, allowing you to stack more tiers within reaching height. Costs less per filing inch than conventional filing cabinets. Tiers feature four welded dividers and reinforced steel shelves that hold materials without "racking." All-welded construction and reinforcing dividers allow for even heavy X-ray storage. Stack up to eight shelves. Easy to install and expand. Add another level by simply removing the top and stacking on another tier.