A filter (10) and an inflator assembly (15) for use in an inflatable vehicle passenger restraint system. The inflator assembly (15) includes an inflator housing (70) having a wall (71), a combustion chamber (72) formed in an interior of the housing (70), and a gas generant composition positioned in the combustion chamber (72) and ignitable to provide inflation gas to the inflatable occupant restraint system. The filter (10) is positioned intermediate apertures (73) in the combustion chamber (72) and apertures (19) in the inflator housing wall (71). The filter (10) includes a filter body (11) spaced apart from the housing wall (71) and at least one continuous lip (12) extending from the filter body (11). The lip (12) has a peripheral edge (75) that abuts the housing wall (71) over substantially the entire perimeter of the peripheral edge (75). The lip (12) aids in positioning the filter (10) within an inflator housing (70) and in maintaining the position of the filter (10) within the housing (70) during passage of combustion gases through the filter (10).