Cover with manuscript 'Lt Cuch A R Gordon, c/o F.P.O. NY City - NY. U.S.S. Sea Robin SS407' return address on front franked with 1931 6c brown AIR issue (SG 128) tied by COCOLI C.Z. duplex cds dated MAR 24 1949. Addressed to USA. The USS Sea Robin was a Balao class submarine which operated between 1944- 1970 and wa based in the Canal Zone between 1945-1949. Scarce.