Airbags designed for automobiles come in all shapes and sizes, ranging from conventional side and front airbags to more unique designs such as knee airbags and inflatable seat belts. Once deployed, airbags can hold from 55 to 120 liters of gas.
Airbag systems do not save lives on their own. They are what we call “supplemental restraint systems”, meaning they must be used in conjunction with (and not instead of) seatbelts in order to be effective
airbags only have one shot. After they have been deployed in an accident, they must be replaced by a professional mechanic.