Registered cover franked with 1924 2c red and 1930 25c purple AIR issue (SG 751 & 777) tied by boxed SAN SALVADOR 'Airplane' cancel with SAN SALVADOR cds dated SET 15 1930 the first day of issue with boxed 'Primer Dia de Circulacion' cachet and boxed registration marking all on front, Sent airmail to NICARAGUA with arrival mark on reverse.