Post cards measure 5.5" x 4".  The post cards come in sets of 25.  Any of the wording can be changed on the card.  They are printed on both sides, so your return address will be printed on the reverse side.  To order, enter the wording and address you would like printed on the card.  Click "Add to Cart" on the right.  Enter the quantity on the next page.  The cards are sold in sets of 25.  If you would like a quantity of 25 total cards, enter quantity "1".  If you would like 50, enter a quantity of "2", etc.