1929. Air Mail envelope addressed to Porto Rico bearing SG 272, 3c green, SG 274, 2c violet, SG 277, 12c orange and purple and SG 278, 24c purple and green tied by 'Foreign Section/British Guiana' double ring with boxed 'British Guiana by Air Mail', underpaid with circular 'T/60c' and United States postage due Yvert 37, 2c carmine and SG 41, 10c carmine tied on arrival by San Juan/Parcel Post double ring. Nice combination.