A bowden cable is a device for the flexible transmission of small mechanical movements, generally to the controls of a machine. It consists of a strong steel cable (usually multi-stranded and lubricated) in a flexible outer tube, often made in the form of a long coiled spring. The outer tube is anchored at the ends so that the inner cable can move independently. Bowden cables are commonly used for throttle (accelerator), clutch, choke, and sometimes brake controls on cars and motorcycles.