Push Back rack systems are available in structural or roll-formed frames. Push Back systems work by placing pallet loads on a series of nesting carts fed forward by gravity on rigid structural steel rails. As a pallet is loaded from the front, it pushes the pallet behind it back one position. When unloading, the front pallet is removed and the rear pallets automatically come forward to the front picking position. This allows for easily accessible Last-In-First-Out (LIFO) inventory management. Operators can store product from 2-5 pallets deep, with front-only loading from a single aisle. Push Back offers more versatile storage than Drive-In rack because each lane flows independently and vertical storage operates separately from lanes below. Multiple pick facings for a variety of SKUs can be stored and retrieved without disturbing other product above or below in a single-lane or double-lane format.