A bowling ball is a piece of sporting equipment used to hit bowling pins in the sport of bowling. Ten-pin bowling balls are typically hard spheres with three holes drilled in them, one each for the ring and middle fingers, and one for the thumb. Regulating bodies such as the USBC maintain requirements for the properties of bowling balls, including size, hardness, and number of holes, as well as maintaining a list of bowling balls approved for competitive play. Other bowling balls, such as those used in five-pin bowling, candlepin bowling, and duckpin bowling are smaller, lighter, and without holes, so that they may be held in the palm of the bowler's hand. Most bowling alleys provide balls for patrons to use within the establishment, often referred to as "house balls."