There are several different sizes of car speakers that can be used in a vehicle's audio system. Some common sizes include:

* 4″ x 6″
* 5″ x 7″
* 6″ x 8″
* 6″ x 9″
* 6.5″
* 7″
* 8″
* 10″
* 12″

The size of the car speakers that you need will depend on the size of your vehicle and the specific audio system that you have. It's important to make sure that the speakers you choose are compatible with your system and will fit properly in your vehicle.