Hong Kong Post issued these sets of four cards in 2012.  Each set commemorates a different festival:  Tuen Ng (Dragon Boat), The Birthday of the Buddha, Kwun Yum, and Tin Hau.  Each card has pre-printed airmail postage corresponding to the card’s design, good for anywhere in the world.  We have four unused sets available, all in their original cello-wrap, and here is how they are different from each other:  Two sets have no postmarks (Grades: 1, $22).   One set has a special “Hong Kong Philatelic Bureau” postmark on each card, with date of issue (Grade: 1, $28).  One set has a special “Hong Kong Festivals” postmark, also on each card and also with date of issue (Grade: 1, $28).