Freewheels are machine elements specific characteristics: - in one direction of rotation, there is no transmission between internal and external rings; allowing free turning of freewheel; - in other direction of rotation, there is transmission between internal and external rings; and in this direction it is possible to transmit a high torque. Such characteristics allow the freewheel to perform several functions in a completely automatic manner on many different machines. They do not require mechanical or hydraulic equipment to control them, as in the case of brakes and clutches. Freewheels are used as: - indexing freewheel (advance); - overrunning coupling; - backstop. Freewheels are essential construction elements in automotive and machine industry, as well as for aeronautical technology. The freewheel, as a self-controlled activation element, is preferred over conventional solutions, because it offers decisive advantages, such as: - operating safety - economy; - high automation level.