Audi advanced key-keyless start, stop and entry

A key to let your Audi recognize you. The advanced key is identified via proximity sensors in each vehicle door and the trunk lid, matched to a radio pulse generator in the key. When approaching the vehicle, the driver can unlock it with the key still in his or her pocket. From within, the vehicle can be started with the push of a button.
Disclaimer:
See Owner’s Manual for further details and important warnings about the keyless ignition feature. Do not leave vehicle unattended with the engine running, particularly in enclosed spaces.