The airbag unit is disposed inside the rear upper face portion of the instrument panel near the difference-in-level portion. Also disclosed is the method for manufacturing the float of this invention including the steps of milling acrylonitrile rubber, phenolic resin, sulfur and various additives in a Banbury mill and mixing at an elevated temperature below 250, compression molding at up to 900 psi pressure between 250 and 350 F. The high pressure suppresses the boiling point of liquids, thus allowing higher temperatures to be used to optimize reactivity.