Abstract: An air bag inflator (14) includes a pressure vessel (40), an initiator (42) and a filter (38). The pressure vessel (40) has a sealed chamber (44) containing inflation fluid under pressure, and includes a rupturable closure wall (100) which blocks the inflation fluid from exiting the chamber (44). The initiator (42) releases the inflation fluid to exit the chamber, and includes a casing (122) centered on an axis. The casing (122) contains pyrotechnic material which, when ignited, produces combustion products for rupturing the closure wall (100). The filter (38) is a sintered metal screen which filters the inflation fluid. The sintered metal screen (38) has an elongated tubular shape extending longitudinally over the casing (122) radially outward from the casing (122).