Clay Court (Chamot) is one of many different types of tennis courts. Clay courts are made of crushed slate, stones, bricks or other unbound mineral aggregates. French Open uses clay courts, making it unique among Grand Slam tournaments. Clay courts are more common in continental Europe and Latin America than in the United States, Canada or the United Kingdom. Although it is cheaper to construct than other types of tennis courts, the maintenance costs of the clay are high, as the surface has to be rolled up, Chamot is added periodically to preserve the good playing surface. The water content must also be balanced; good drainage is required, can be filled with a specialized irrigation system for easier use.