Who doesn’t love tennis balls, and especially when it's bouncing along to spell a very special "Happy Birthday" greeting? The A4 size, 4 1/4" x 5 1/2", cards are printed on heavy 110 lb. cardstock. The card outside is printed with "Happy" while the inside shows "Birthday!" The card inside also has ample room for you to write a personal message, if you wish. Cards come in packs of 4, presented in an attractive, handmade cardstock folder (paper designs are varied and chosen by us) and wrapped in cellophane for protection. For your convenience, heavyweight envelopes are included.