Iridescent Monarch Butterfly Foil Balloon 30 . There is 1 foil balloon in a pack. The balloon needs helium to be inflated. It is automatic self sealing. The size is approximately 30 inch or 76 cm . WARNING: CHOKING HAZARD - Children under 9 years old can choke or suffocate on uninflated or broken balloons. Adult supervision is required. Keep uninflated balloons from children. Discard broken balloons at once.