Rubber bands (more commonly known as Bungees in the skydiving world) are rings of latex used for binding purposes. They are manufactured using either synthetic or natural rubber (the natural variety has superior elasticity) which are harvested from the latex in the bark of the rubber tree. The latex becomes hard and develops elasticity once exposed to air. During manufacturing, the latex is poured into a tubed device to obtain the ring shape. After it has been cured under heat, they are sliced into thin bands.