• Air balloon number size: 40"/100 cm aluminum balloon (before inflating). It is ideal decoration for birthday parties. • Easy to inflate: aluminum balloons can be filled with helium or air. Blow up the balloon with a straw or a hand pump. The valve closes automatically and holds the air well. • Birthday decoration set: blue balloons are a popular birthday decoration for boys, girls, men, and women. • High quality: high-quality foil balloon is thickened, non-toxic. If the large numbers are filled with helium, they will float for up to 8 days. • Little money but fun: the huge helium balloon fly is the best value for money for birthday decoration.