These Metro security carts are constructed of heavy-gauge open-wire to ensure your contents are visible and easily managed. These carts utilize genuine Metro shelves and wire-grid panels to create a sturdy, cost-effective, and lockable storage unit. Optional adjustable wire shelves can be positioned at precise 1" increments along the length of the numbered posts. The open-wire design minimizes dust accumulation and allows for air circulation. These heavy-duty carts have aluminum dolly bases with wrap-around bumpers and plate casters. There are two swivel and two braking casters with 5" polyurethane wheels rated for 300 lbs. each. The cart is rated for 900 lbs. but should be limited to 750 lbs. for over-the-road applications. Internal shelves are not included.