Official Rules of Racquetball
2.2 - Ball Specifications
(a) The standard
racquetball shall be 2 1/4 inches in diameter; weigh approximately 1.4
ounces; have a hardness of 55-60 inches durometer; and bounce 68-72
inches from a 100-inch drop at a temperature of 70-74 degrees
(b) Only a ball having the approval of the USAR may be used in a USAR sanctioned tournament.