The cat knows $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". The cat knows quantity Add to cart Categories: Hearts, Pets. Tags: cat, cat greetings, pet, pet greetings. Related Products I Love You from the Bottom of My Heart $20.00 Thanks for Your Strength $20.00 In Deep $20.00 You Are So Good to Me $20.00