Christmas to the Core $20.00 Inside Message Blank Inside Packages of Heartstrings® cards are shrink-wrapped and sold in sets of 10 cards with envelopes. The actual card size is 4 1/4" x 5 1/2". Christmas to the Core quantity Add to cart SKU: 690. Category: Christmas - Holiday. Related Products Warm Christmas Wishes $20.00 A Little Peace of Christmas $20.00 Fat, Tired and Merry $20.00 One if by Land $20.00