An airbag for a vehicle occupant protective system comprises an inflatable cushion, a cinch tube circumventing a vent aperture disposed in the cushion, and a draw element guided in a circumventing channel of said cinch tube and being coupled to a surface of said cushion such that deployment of said cushion causes said draw element to contract said cinch tube. The airbag comprises a contraction limiting arrangement adapted to limit the contraction of said cinch tube by said draw element to a predetermined minimum free diameter d of at least 20% relative to the free diameter D of the open cinch tube.