Airbag

An airbag comprising an outer wall having a front wall and a rear wall, a tether provided inside the airbag, and an electrically actuatable activation unit for releasing the tether so that the latter no longer develops a restraining effect, wherein the airbag adopts a large or a small inflation volume depending on the actuation of the activation unit, wherein the tether comprises plural tether portions coupled to each other via a first tear seam, and to the activation unit a tension means is coupled which is coupled at its front end region to the first tear seam so that, when the activation unit is actuated, the first tear seam is destroyed by tension and, during inflation and lacking actuation of the activation unit, the first tear seam remains intact and the airbag has the smaller inflation volume.