Abstract: A filter, seal and port arrangement for a pyrotechnic air bag inflator. The seal consists of a ring or annulus of sheet metal which has a foot section abutting against the filter, and a leg section of the seal angled to form an interference fit against an interior wall of the generator housing. For annular filters used in axial flow inflators, a ring is used at the radially inner and outer edges of the annular filter. For tubular filters used in radial flow inflators, a single seal at a longitudinal end may be sufficient. With such tubular filters, the seal may include a stand-off to form an annular void between the radially outer face of the filter and the wall of the housing. This void will act as a plenum to ensure that a greater volume of the filter is used. The tubular filter itself may also be formed with raised lands such that the interposed grooves form such a plenum. In a similar manner the disk filters may also have plenum producing lands on their outer faces, or the housing may include such lands.