1 Jul 1972 to 1 Mar 1974
US foreign surface letter rate 15 c
Swedish foreign surface letter rate 100 öre
US handstamp shows amount to pay in US cents (normally double deficiency) and US surface letter rate.
In Sweden the indicated fraction multiplied by 100 rounded up to nearest 5 öre was normally paid by affixing stamps on the item.

Unfranked single rate air mail letter. Correct rate 21 cent. Shortpaid 21 cent. US due handstamp indicates double deficiency 42 cent and foreign letter rate 15 cent. 42/15 of 100 öre = 280 öre have been indicated on the due label and paid by affixing stamps on the item.