1. As a child, many people will probably use this "key" for starting cars, tractors and the like. It is also commonly used in diesel engines.

2. The traditional key can be used to start the car after the development of the car into the era of electronic ignition, also known as the blade key.

3. Remote control and chip key. With this chip key, anti-theft ability has been improved.

4. The integrated remote control key is mainly the combination of the remote control and chip key, which greatly improves the portability of the key and is also the mainstream car key.

5. Remote control intelligent keys, intelligent car keys, get rid of the design of car chip keys, and use intelligent main body to realize the multi-functional operation of the car, which is often seen in some high-end models.