The document discusses letters of credit and letters of guarantee. A letter of credit is a payment undertaking issued by a bank on behalf of an importer to provide secure payment terms to an exporter. It guarantees payment to the exporter if they present complying documents within a specified timeframe. A letter of guarantee is similar, but issued by a bank on behalf of a customer to guarantee payment to a supplier in case of a transaction failure by the customer. Both mechanisms provide assurance of payment to beneficiaries if certain terms are met.