T1 (external transit) is used for non-Union goods (from third countries) crossing the EU/EFTA customs territory. Goods travel under customs bond without intermediate duty payment until the destination customs office. T2 (internal transit) is used for Union goods that must cross non-EU territory (typically Switzerland) while maintaining their Community goods status. For example, Italian goods transiting through Switzerland to reach Germany travel with a T2 document, avoiding double customs clearance. Both are managed electronically via the NCTS system and require a financial guarantee (bond or cash deposit) covering potential duties. Each operation is identified by a unique MRN code.