A lifting bag is an item of diving equipment consisting of a robust and air-tight bag with straps, which is used to lift heavy objects underwater by means of the bag's buoyancy. The heavy object can either be moved horizontally underwater by the diver or sent unaccompanied to the surface. Besides as a piece of diving equipment there are also lifting bags used on land for lifting cars or heavy loads or lifting bags which are used in machines. These lifting bags of the AS/CR type are for example used in the brake mechanism of rollercoasters]