A Strip of Five United States 1938 Dark Blue & Carmine Airmail with a Vertical Imperforate Pair 6-Cent Stamps #C23b with certification from The Philatelic Foundation, stating: 'Unused, OG, Genuine, Never Hinged, except previously hinged in the margins at left and right; the error pair with a faint diagonal crease at top left and both stamps with faint vertical crayon marks', together with a block of six and block of twelve #467 carmine 2/5-cent error and a single and a plate-block of eight 1918 Curtiss Jenny double-transfer 6-cent stamps.

Literature: The sheet from which this strip came was advertised on December 14, 1940 by Emil Bruechig. The imperforate pair represents positions 16 and 17 on the sheet.