: Feature distinctive winding cuts on the side rather than the edge, offering higher security and requiring specialized machinery to duplicate.
: Combine a key for the ignition with a remote for locking/unlocking. These often include "panic" buttons and trunk release.
: Contain a small electronic chip in the plastic head that communicates with the car's immobilizer. If the wrong signal is detected, the car will not start.
: Basic metal keys with no electronic components. These are the simplest to replace, requiring only physical cutting.