The direct put-away activity involves transferring of (if applicable repacked, i.e., from
pallets to cases) incoming products to a location within the storage area. A product kept in
stock is also called a stock keeping unit (SKU). Each product or SKU has an identification
code that allows it to be tracked for inventory purposes. During the course of a year, the
entire inventory of a product or SKU can be replenished multiple times. The storage area
of a warehouse may consist of two parts: a reserve area, where products are stored in the
most economical way, and a forward area where products are stored for easy retrieval. A
forward storage area is replenished from a reserve storage area. A wide range of systems
can be used to store products, varying from shelf racks to automated storage systems.