Wack-A-Pack 12 HAPPY BIRTHDAY Mini Balloons - whack the bag to inflate them 3 packages of 4 mini balloons Smack the pack firmly and then watch the balloon emerge from the packaging Balloons are approximately 3.75 inches inflated. 4 different designs (3 of each). May vary among those pictured. Great for parties or gag gifts. Ages 4+ Fun self-inflatable balloons on make the perfect birthday surprise! Each pack contains 4 individual foil gifts with to/from lines and a picture of birthday sentiment. The kids can then smack the package and watch as the balloon inside inflates and bursts from the package. Inflated balloons measure approximately 3". Fun for friends, neighbors, and classroom gift exchanges, novelties.