From this Buddhist Memorial Center itself, we have two of these, in their original cellowrap.  The card is made of plywood, 1/4″ thick, and has a hole in the top with a small cord (included) so you can hang the card somewhere.  One of these is unused (Grade: 1, $8) and the other was mailed (by us) with stamp and partial postmark.  The postal clerk insisted that the stamp would not stick to the card, and demanded to put some tape across the top of the stamp to hold it in place.  If we wanted to mail it then and there, we had no choice.  Just FYI, the untaped part of the stamp stuck just fine (Grade: 2, $8).