This Down Payment Bank Guarantee shall be valid only when and after the payments by the Purchaser under this Sub-clause (a) has been made and be reduced automatically and sequentially by the percentage of the Contract Value of the total Contract Price for which CIF Yangon has been confirmed on presentation of shipping documents to the Contractor's nominated Bank, by the Contractor and expire with the final invoiced CIF Yangon under this Contract. All expenses and costs payable in connection with the above mentioned Down Payment Bank Guarantee shall be on account of the Contractor. Form of Down Bank Guarantee attached hereto as Annexure (4).