Gravity flow storage systems consist of two elements: a static rack structure and dynamic flow rails. The flow rails are a track & heavy-duty roller system set at an incline along the depth of the rack.  Pallet loads move along the rails

by gravity from the loading end (typically the back) to the unloading end (typically the front).   Each flow lane includes self-energized speed controllers (brakes) to control the speed of movement within each lane.  As a pallet of product is removed, the loads behind it move forward to the unloading position.  Gravity flow storage systems are generally utilized where storage density and inventory rotation (first-in and first-out) are priorities.