The packing slip is included with a shipment and itemizes the contents of the shipment. It should include quantity, item number, and item description, but does not necessarily need to include price. A buyer will take the packing slip and reconcile with a count of the physical goods in the shipment, and make sure the item count matches their purchase order. This insures that there is not an over ship or short ship, and that all items shipped match what was originally ordered.