Self-assessment of customs duty required: electronic filing mandated, subject to verification, re-assessment and provisional assessment procedures. Self-assessment of customs duty requires importers and exporters to file Bills of Entry and Shipping Bills electronically, declaring correct classification, value, duty rate and exemptions; electronic filing is default, with manual filing only in exceptional, authorised cases. Declarations are subject to selective verification via the Risk Management System, including examination, testing and document production; incorrect self-assessments may be re-assessed by the proper officer, and provisional assessment with security may be used where immediate re-assessment is not feasible.