Push back pallet rack systems are gravity flow systems that store pallets on carts with rail and wheel bases for improved storage and rotation. The racks are slightly angled toward the front, letting gravity help fill the front of the rack where goods are loaded or unloaded. It operates on a Last In First Out (LIFO) system. The goal of a push back racking system is to store more pallets within one's warehouse space, but also giving forklift operators the ability to access pallets more easily. This adds more efficiency to inventorying and picking. In fact, 90% more storage space can be offered than selective pallet racking since the high-density systems typically are two to six pallets deep.