Car replacement keys are made to replace a lost or stolen key for a specific car. There are many different types of car replacement keys, but they all serve the same purpose: to allow the owner of a car to have a backup key in case their primary key is lost or stolen. A transponder key, which uses a chip to interact with the car's ignition system and unlock the doors, is the most common type of car replacement key. Other  types of car replacement keys include traditional met