appreciated that the tabs 12 will also assist in spacing the flange member 8 of the gas generator 2 and the base plate member 3 the same predetermined distance apart it is envisaged that the predetermined distance apart will be between 2 millimetres and 10 millimetres it is to be further appreciated that when the above arrangement is assembled as has been described the apertures 20 and further apertures 21 provided around the periphery of the opening 19 of the fabric layer 17 of the air bag 4 are permitted to slide along the studs 9 and the tabs 12 respectively thus the part of the first fabric layer 17 of the air bag 4 adjacent to the opening 19 may move from a position adjacent the flange member 8 of the gas generator 2 to a position adjacent the base plate member 3 referring now to fig2 in an accident situation gas will be injected from the gas generator 2 into the air bag 4 in a direction substantially as shown by arrow 23 this direction of flow of gas from the gas generator 2 will give the entire air bag momentum in the direction shown by the arrow 23 and the first fabric layer 17 will be.