Cricket balls are made from a core of cork, which is layered with tightly wound string, and covered by a leather case with a slightly raised sewn seam. The covering is constructed of four pieces of leather shaped similar to the peel of a quartered orange, but one hemisphere is rotated by 90 degrees with respect to the other. The "equator" of the ball is stitched with string to form the seam, with a total of six rows of stitches. The remaining two joins between the leather pieces are left unstitched.
For men's cricket, the ball must weigh between 5.5 and 5.75 ounces (155.9 and 163.0 g) and measure between 8 13/16 and 9 in (224 and 229 mm) in circumference. Balls used in women's and youth matches are slightly smaller.
Cricket balls are traditionally dyed red, and red balls are used in Test cricket and First-class cricket. White balls were introduced when one-day matches began being played at night under floodlights, as they are more visible at night. Professional one-day matches are now played with white balls, even when they are not played at night. Other colors have occasionally been experimented with, such as yellow and orange for improved night visibility, but the coloring process has so far rendered such balls unsuitable for professional play because they wear differently to standard balls. Recently the ICC is in talks for testing with pink balls in ODI matches. The white ball has been found to swing a lot more during the first half of the innings than the red ball and also deteriorates more quickly.
Cricket balls are expensive. As of 2007, the ball used in first class cricket in England has a recommended retail price of 70 pounds sterling. In test match cricket this ball is used for a minimum of 80 overs (theoretically five hours and twenty minutes of play). In professional one day cricket, at least two new balls are used for each match. Amateur cricketers often have to use old balls, or cheap substitutes, in which case the changes in the condition of the ball experienced during an innings in professional cricket are not replicated.
