In the early days of tennis, balls were often made of leather stuffed with hair or wool. Early tennis balls were made by Scottish craftsmen. These tennis balls were commonly made from a wool-wrapped stomach of a sheep or goat and tied with rope. Those recovered from the hammer-beam roof of Westminster Hall during a period of recent restoration were found to have been manufactured from a combination of putty and human hair, and were dated to the reign of Pope Leo X. Other versions, using materials such as animal fur, rope made from animal intestines and muscles, and pine wood, were found in Scottish castles dating back to the 16th century. In the 18th century, ¾" strips of wool were wound tightly around a nucleus made by rolling a number of strips into a little ball. String was then tied in many directions around the ball and a white cloth covering sewn around the ball. This type of ball, but with a rubber core, is still used for the original game of tennis, today called real tennis. With the introduction of lawn tennis in the 1870s, vulcanized rubber was first used to manufacture balls, often in tubes of four with a package, but not with the name of the brand.

Tennis is an outdoor or indoor game, which is played on a rectangular court by two persons (known as singles) or by four persons (doubles). Rackets are used to hit the ball back and forth across a net. The object of the game is to score points by striking the ball in a way that an opponent can not successfully return it. The origins of the game dates back to the Stone Age, when humans first used their clubs to hit rocks back and forth across barricades of dirt and stone. The tennis court is 78 feet (23.8 meters) long, and its divided into equal sides by a net that stands 3 feet (0.9 meters) high at the center of the court. For singles, the court is 27 feet (8.2 meters) wide. For doubles the width is increased to 36 feet (11 meters). A tennis ball is hollow and composed of inflated rubber, covered with a fabric which must be uniform. Its between 2½ and 2 5/8 inches (6.35 and 6.67 cm) in diameter and weighs between 2 and 2 1/16 ounces (57.7 and 58.5 grams). Yellow and white balls are used in competition. When dropped on concrete from a height of 100 inches (2.5 meters), they must bounce upward from 53 to 56 inches (135 to 147 centimeters). The serve is the most important stroke in tennis. There are no weight restrictions on the racket and it is usually strung with resilient gut or nylon. The surface of the court may be grass, clay, or some kind of hard material which is usually concrete, asphalt, synthetic turf, or wood. The court surface is an important element in tennis because balls bounce higher or lower, faster or slower, depending on the surface they strike. There is a tendency to slide on clay while harder surfaces are ideal for quick starts and stops.