U.S. #BK226B $6.40 (Blue) Flag Over Porch Book of 15 (#2920h)
#2920h is a pane of 16 with one stamp removed.The missing stamp is the lower right stamp in the pane, or more rately the upper left stamp. The #2920h cannot be made from No.2920f. If the label is removed from #2920f, an impression of the die cutting appears on the backing paper.
BK226A-B and BK227 are called makeshift vending machine booklets. These booklets, plus BK273-BK258, are known as 'The Blues' for the blue cover jacket they share in common. The text on the front and back changs to describe the contents of the booklet.