What is a belt bag?

The waist bag is a combination seat belt and airbag introduced in 2009 by Mercedes-Benz. The inflatable seat belt is designed to reduce the pressure of the seat belts on the occupant's body in the event of a vehicle collision. This seat belt can double its width in a fraction of a second. The volume of the bag is approximately 4 liters and should help passengers in the rear seats, where there are no conventional front airbags.