A method of filling an order in a warehouse or store. An order is received at a product moving device, and is filled with items in the warehouse. The order is displayed as a picklist that includes data about each item, including the number of the item desired, and any special loading considerations. As items are placed on the device, an RF reader on the device detects the item, and removes the item from the picklist. If an item not on the list is loaded on the device, the system detects the item, and notifies the operator. The item must be removed, or allowed to remain, before any other items are loaded.