The Grand Slams are the four most prestigious tennis tournaments in the world. Each tournament uses a different type of court surface, which affects the way the players play the game. The Australian Open uses a hard court, the French Open uses a clay court, Wimbledon uses a grass court, and the US Open uses a hard court. The type of court surface affects the speed of the game, the ball bounce, the player's footwork, and the spin that can be applied to the ball. The different surfaces also require different types of footwear, meaning that players must be prepared to change their footwear depending on which Grand Slam they are playing.