A mechanized approach to case or piece picking where inventory is most commonly stored on both sides of a powered conveyor. Usually, there are multiple levels of pick modules, often 2-4. As picks are completed, the cartons or totes are placed on the conveyor for takeaway, either to another zone (for piece picking) or level, or to shipping for completed piece picks or full carton picks. There are many permutations to this basic theme, such as whether the transfer of the totes to different zones is mechanized, whether a carton/tote can recirculate at the end back to an earlier zone where a pick was shipped and more. Pick modules are closely associated with downstream sortation processes after cartons leave the pick modules.