Canal Zone, 1918, 1c green & black, horizontal pair, tied by two strikes of "Balboa, C.Z., Dec 2, 1918" duplex postmarks on YMCA corner card cover cover to Indianapolis, Ind., Very Fine, sent from sailor aboard the "U.S.S. Delong, U.S. Navy". Scott No. 52  Estimate $150 - 200. $0 (Image)