"Law 4: The ball". A cricket ball is between 8.81 and 9 inches (22.4 cm and 22.9 cm) in circumference, and weighs between 5.5 and 5.75 ounces (155.9g and 163g) in men's cricket. A slightly smaller and lighter ball is specified in women's cricket, and slightly smaller and lighter again in junior cricket (Law 4.6). Only one ball is used at a time, unless it is lost, when it is replaced with a ball of similar wear. It is also replaced at the start of each innings, and may, at the request of the fielding side, be replaced with a new ball, after a minimum number of overs have been bowled as prescribed by the regulations under which the match is taking place (currently 80 in Test matches). The gradual degradation of the ball through the innings is an important aspect of the game.