Inventory within the VLM is stored on front and rear tray locations or rails. When a tray is requested, either by entering a tray number in the built-in control pad or by requesting a part through software, an extractor travels vertically between the two columns of trays and pulls the requested tray from its location and brings it to an access point. The operator then picks or replenishes stock and the tray is returned to its home upon confirmation.