The HS code (Harmonized System) is an international goods classification managed by the WCO, used by 200+ countries and territories. Hierarchical structure: first 2 digits = chapter (e.g. 87 = vehicles); 4 digits = heading; 6 digits = subheading (worldwide harmonised). Countries add national digits: Switzerland uses 8 (Tares); EU uses 8 (Combined Nomenclature CN) + 2 (TARIC = 10 digits); UK uses 10 (UK Trade Tariff). Correct classification is crucial as it determines: duty rates (weight-based in Switzerland); preferential agreement applicability; restrictions, quotas or licences; documentary requirements. For complex cases, a Binding Tariff Information (BTI) can be requested, valid for 3 years in Switzerland and 6 years in the EU. Misclassification can result in back-duties, penalties and delays.