So small, we’re not even certain we would be allowed to mail these in Hong Kong.  A set of six unused 3-1/8″ x 4-7/8″ cards issued by China Post in 2016.  Our scan shows the front of its cardboard cover, which is also the essence of one of those six cards.  Each card has pre-printed, coloured 80 fen postage.  Grade: 1