Getting the most out of every inch is easier than ever with Metro Top-Track High-Density Storage Systems. Take advantage of these great benefits: Floors are easier to clean. Utility carts can be rolled into and out of the active aisle. The guide track on top compensates for uneven floor surfaces and keeps units in alignment. Mobile units are designed to address medium-duty applications. The weight capacity of each Top-Track mobile unit is 900 lb. (410kg). Super Erecta Metroseal Gray shelves feature Microban antimicrobial product protection to keep the product “cleaner between cleanings” and protect against rust and corrosion.