A volleyball is made out of a rubber core, known as a "bladder," which is wrapped with cloth. The outer layer of the volleyball is made from leather.
While different volleyballs are used for indoor and outdoor play, they are both made of the same materials. Indoor volleyballs are generally white or tri-colored while outdoor balls are usually either white or brightly colored.
Traditionally, the exterior leather surface is divided into 18 panels, although the official indoor volleyball for the 2008 Olympic games was an 8-panel design. The design has since become the official game ball of the International Federation of Volleyball.