It must be not less than 12.5 inches (32 cm) or more than 15 inches (38 cm) in circumference. The weight must be not less than 170 grams (6.0 oz) or more than 182 grams (6.4 oz). In a bounce test from 9 feet (2.7 m) on concrete at 70 °F (21 °C), the rebound should be a minimum of 54 inches (140 cm) and a maximum of 64 inches (160 cm) at the inflation rate specified by the manufacturer.