6c blue postal stationery envelope (H&G B113) used with added 1925 2c on 60c violet 'Fourth Centenary of San Salvador' issue (SG 760) tied by SAN SALVADOR cds dated 2 AGO 1925 (possibly first day of issue) postage was evidently underpaid and then additionally franked with 1925 2c red (SG 751) overlapping the first postmark and tied by different SAN SALVADOR cds dated 3 AGO 1925. Addressed to SPAIN with BARCELONA arrival mark on reverse.