A single bill of lading converting both the domestic and international carriage of an export shipment. An air waybill, for instance, is  essentially a through bill of lading used for air shipments. Ocean shipments, on the other hand, usually require two separate documents - an inland bill of lading for domestic carriage and an ocean bill of lading for international carriage. Through bills of lading are insufficient for ocean shipments. Compare Air waybill, Inland bill of lading and Ocean bill of lading.