Keyless Go is a system designation for the use of vehicles without active use of a car key. Common keys are replaced by modern car keys, which have a safety mechanism and can open and close vehicle doors by radio. Either as soon as the key is in a certain radius around the vehicle or by pressing the button on the key. Radio keys are also used in easy-entry and keyless-go systems of more modern vehicles. Starting the vehicle engine by pushing a button in the dashboard also depends on the presence of the associated radio key. If necessary, the door can usually also be closed mechanically via a closing cylinder. They radiate in the range of 433 MHz in the ISM band. A precursor technology of the radio keys were infrared-emitting car keys. In the case of new vehicles, a transponder (RFID chip) is integrated into the key, the data of which is necessary to release an immobilizer. The opening and closing of the glove compartment and the fuel filler cap, as well as the activation and deactivation of certain airbags, are further functions of modern automotive keys.