The specifications for tennis balls are defined by the International Tennis Federation (ITF). This means the ball must be a certain size and weight and made with certain materials. Tennis balls are made of 2-piece rubber cores that are cemented together. This is then covered with fabric, usually wool or synthetic felt. The seams between the two pieces of the core are exposed, but covered with elastic sealant.
The ITF defines the official diameter as "more than" 2 and 1/2 inches but "less than" 2 and 5/8 inches. The weight is "more than" 2 ounces but "less than" 2 and 1/16th ounces.
The rules also say that, when dropped onto a concrete base from 100 inches, the ball should bounce "more than" 53 inches but "less than" 58 inches. In order to achieve this, most balls are pressurized and filled with air.
Finally, the rules state that the "stiffness" of the balls, defined by how much they deform (curve in or out) at 18 lbs of pressure, must be "more than" .220 inches and "less than" .290 inches for forward deformation. For return deformation it must be "more than" .315 inches and "less than" .425 inches.
Matt: WRONG
Record: 51-30
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