Squash is a racquet sport played by two (singles) or four players (doubles) in a four-walled court with a small, hollow rubber ball. Squash’s use of stringed racquets is shared with tennis. The players must alternate in striking the ball with their racquet and hit the ball onto the playable surfaces of the four walls of the court.
In the 19th century the game increased in popularity with various schools, clubs and even private citizens building squash courts, but with no set dimensions. In April 1907 the Tennis, Rackets & Fives Association set up a sub committee to set standards for squash.
Squash balls are between 39.5 and 40.5 mm in diameter, and have a mass of 23 to 25 grams.They are made with two pieces of rubber compound, glued together to form a hollow sphere and buffed to a matte finish. Different balls are provided for varying temperature and atmospheric conditions and standards of play.