What is the official size and weight of a volleyball?

The size of the ball varies according to the classification of play; the permitted circumferences in international play are 12" (30.5 cm) and 11" (27.9 cm). In fast Pitch 12" is standard but in slow pitch 11" or 12" can be used. The ball is most often covered in white leather in two pieces roughly the shape of a figure 8 and sewn together with red thread, although other coverings are permitted. The core of the ball may be made of long fibre kapok, or a mixture of cork and rubber, or a polyurethane mixture, or another approved material. In 2002, high-visibility yellow "optic" softballs were introduced. For a 12" ball the min weight is 178.0g (6 1/4oz.) and a max of 198.4g (7 oz.) and for an 11" ball 166.5g (5 7/8oz.) is the min and 173.6g (6 1/8oz.) is the max. Information was found in the Official Rules of Softball (International Softball Federation) In Chicago, where softball was invented, it remains traditional to play with a ball 16 inches in circumference, with other attributes of the ball remaining the same.