From The Website:
1. The balloon will seal with no leaking automatically after flated. Then shake it up and down for a little while, touch the surface of balloon with hand, the inside colorful foam and paillette will move as your hand move.
2. Notes: Please use inflator to inflate this model of balloon, otherwise there will be no static.
1. Material: Latex
2. Size: about 12 in
3. Specifications: Fours bags with 5 pieces in each bag.