Effective April 10, 2008, we are revising Mailing Standards of the United States Postal Service, International Mail Manual(IMM®) 770 to add International Surface Air Lift® (ISAL®) to the list of undeliverable-as-addressed First-Class Mail International™ products that a foreign postal administration may return to the U.S. sender without beingsubject to the payment of return charges.
770 Undeliverable Mail
771 Mail of Domestic Origin
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771.5 Return Charges for First-Class Mail International
771.51 General Procedure
Except as noted in 771.52, undeliverable-as-addressed First-Class Mail International mail that a foreign postal administration returns to the U.S. sender is not subject to the payment of return charges. This provision applies to postal items that were originally entered at the following rates of postage: