Abstract: An order filling system utilizes a server computer, a controlling computer and location verification devices to direct an orderfiller to order items stored in an inventory storage area. The server computer transmits order information to the controlling computer via wireless radio frequency communications. The controlling computer communicates with location verification devices via short range wireless communications. The controlling computer provides the orderfiller with directions and pick quantities for each inventory item in an order. The location verification devices and location clips are mounted throughout the inventory area and on the inventory carriers. The location verification devices may have a low power mode which conserves electrical power while the location verification device is not being used.