Abstract: An air bag initiator including a main body and squib. The squib includes a charge mounted in a charge holder, a header press fitted onto the charge holder and a cup welded to the header. The squib also includes first and second lead pins and a bridgewire. A cap snap fits onto the main body and holds the squib in place during subsequent assembly operations. Ferrite beads for frequency attenuation and potting material are located in a cavity of the main body. The first lead is mounted off center in a bore passing through the header to allow bridgewires of different lengths to be used with the same header design. The cup includes a depression to maintain a single explosive powder charge under pressure and in contact with the bridgewire. An outer cup can be welded to the housing and an insulating cup can be provided between the cup of the squid and the outer cup to provide enhanced hermetic sealing of the charge and prevent current from passing between the cups.