The Audi R18 Mans Prototype car

Sports prototypes, unlike GT cars, do not rely on road legal cars as a base. They are closed wheel and often closed cockpit purpose built race cars intended mainly for endurance racing. They have much lower weight and more down force compared to GT cars making them much faster. They are raced in the 24 hours of Le Mans and in the Le Mans series, Asian Le Mans Series and the United SportsCar Championship. These cars are referred to as LMP cars with LMP1 being run mainly by manufacturers and the slightly less powerful LMP2 cars run by privateer teams. All three Le Mans Series run GT cars in addition to Le Mans Prototypes; these cars have different restrictions than the FIA GT cars.