A Formula One car is a single-seat, open-cockpit, open-wheel formula racing car with substantial front and rear wings, and an engine positioned behind the driver, intended to be used in competition at Formula One racing events. The regulations governing the cars are unique to the championship and specify that cars must be constructed by the racing teams themselves, though the design and manufacture can be outsourced. Modern-day Formula One cars are constructed from composites of carbon fibre and similar ultra-lightweight materials. The minimum weight permissible is 740 kg (1,631 lb). including the driver but not fuel. Cars are weighed with dry-weather tyres fitted.[3] Prior to the 2014 F1 season, cars often weighed in under this limit so teams added ballast in order to add weight to the car. The advantage of using ballast is that it can be placed anywhere in the car to provide ideal weight distribution. This can help lower the car's centre of gravity to improve stability and also allows the team to fine-tune the weight distribution of the car to suit individual circuits. FILE FORMAT: