Balzac Balloon Ball; It's a Balloon in a Sac. Put the balloon in the fabric cover. Blow it up until it tightly fills the entire sack. The tighter and harder the ball, the more fun it is to play with! Tie off the mouth of the balloon and push the knot into the sack. The balloon takes on the strength of the fabric cover. Now you are ready to play - indoors or outdoors!