Heart at Work $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". Heart at Work quantity Add to cart SKU: 206. Category: Hearts. Related Products Thanks for Your Strength $20.00 Bless Your Heart $20.00 Wishing You a Bee-You-Tea-Full Day $20.00 Art is Therapy $20.00