The outside of a basketball is made of synthetic rubber, rubber composition, or leather. The inside consists of a bladder (the balloon-like structure that holds air) and the carcass. The bladder is made of butyl rubber,and the carcass consists of treads of nylon or polyester. Preprinted decals are used to label the ball, or foil is used to imprint label information. Zinc and cooper plates are used to press to either affix the decals or imprint the foil.
The actual configuration of most basketballs is dictated by the rules or standards of the type of game in which the ball will be used. NBA, WNBA, and other professional leagues have specified dimensions for regulation balls, Amateur sport bodies have also developed rules and specifications, and there are specialized basketballs made for junior players (younger than high-school age), intermediate players (high-school age), and for indoor, outdoor, or combination play. Promotional basketballs that are much smaller in diameter are also made as souvenirs of many events such as the NCAA Championship.
Basketball designers are always trying to improve the product and build a better basketball. Inventor Marvin Palmquist created the "Hole-in-One" basketball to improve a player's grip; the ball has dimples, much like a golf ball, and can be easily palmed Michael Jordon-style by players with smaller-than-Jordan hands. Even the most skilled NBA star copes with sweaty palms, and this obstacle is addressed in another modification consisting of microscopic holes in the surface, which is made of absorbent polyurethane. This is the same material that forms the grip on a tennis racket, but it has been strengthened to withstand the abrasion of bouncing on a wooden basketball court. It absorbs moisture to keep the ball's hide less slippery.