rubber basketball: rubber cover, polyester winding, rubber bladder, official size and weight (1) Material: rubber of good quality.(2) Official Size & Weight: 7#, 6#, 5#, ... 3#, 2#, 1#.(3) Bladder: made of good quality rubber/butyl, and wound with strong fabric to enhance and protect ... , and also good quality. All because we are professional factory. Rubber Basketball