an inflator includes a housing formed by two cups interlocked to provide a tamper - proof enclosure with at least one of the cups formed with indentations for grasping by a tool to facilitate assembly of the cups . in a chamber of the housing is an initiator secured in place by a snap - fit . a canister containing tablets of gas generating material is held in the chamber by an interference fit . a filter is held in place in the housing by a ring - shaped retainer member . passages within the housing direct gases from the initiator to the canister through the filter out of the housing into an air bag with the path of travel changing direction by at least 90 ° to create turbulent flow for enhanced inflator gas production .