Shelves can be repositioned at precise 1" (25mm) increments along the length of the numbered posts. Open-wire design minimizes dust accumulation, allows a free circulation of air, and greater visibility of stored items. Starter units consist of four posts and the indicated number of Super Erecta shelves. Corrosion resistant Metroseal Gray epoxy finish features Microban antimicrobial product protection to keep the product "cleaner between cleanings". 12-year warranty against rust and corrosion.