A child seat is a safety device designed to protect young children while traveling in a car. It is specially designed to ensure that children are securely strapped in and protected during sudden stops or accidents. There are different types of child seats based on the child's age, weight, and height, including:

1. Infant car seats – Rear-facing seats for babies from birth up to about 2 years old or a certain weight limit.
2. Convertible car seats – These can be used rear-facing for infants and then converted to forward-facing as the child grows.
3. Booster seats – For older children, usually from around 4 to 12 years old, helping the car's seat belt fit properly.

Child seats are legally required in many countries to ensure the safety of young passengers and are available in various models, including those with features such as adjustable recline, impact protection, and easy installation systems.