Balloons are given for special occasions, such as birthdays or holidays, and are often used as party décor. Party balloons are mostly made of a natural latex tapped from rubber trees, and can be filled with air, helium, water, or any other suitable liquid or gas. The rubber's elasticity makes the volume adjustable. As shown in the photo, they can come in different colors like the rainbow such as red, orange, yellow, green, blue, purple, etc.