NBA balls are made of a leather exterior housing a butyl rubber bladder, which holds the air and creates enough pressure to properly bounce the basketball, and a carcass made of nylon and polyester. There are not any official specifications as to what basketballs should be made of.
Even though there are no specific regulations, the NBA determines that a ball should be 29.5 to 29.875 inches in circumference. In 2006, Spalding, the brand that produces basketballs for official use, introduced a new ball made out of a microfiber composite, which was discontinued due to complaints from players.
