Double Bubble balloons, also known as bobo balloons, are made from a stretchy, transparent plastic material. This material provides a clear or semi-transparent appearance to the balloon. Double Bubble balloons can be filled with air or helium. One of the defining features of Double Bubble Balloons is the second foil balloon already inside the outer deco bubble. They include include two self sealing valves, one for each balloon. To inflate, first inflate the Double Bubble slightly to allow room for the foil balloon to be inflated. Then inflate the foil balloon inside. Finish by fully inflating the outer Double Bubble. Great for centerpieces, gift ideas, bouquets or part of your balloon decor.