A seat belt system for restraining movement of an occupant of a vehicle, said seat belt system comprising: a seat belt (110, 110a), a member (114, 116, 116a, 280) having an opening (204, 204a, 290) through which the seat belt (110, 110a) extends, a first inflatable portion of the seat belt (110, 110a) extending in a first direction from the member (114, 116, 116a, 280), a second inflatable portion of the seat belt (110, 110a) extending in a second direction from the member (114, 116, 116a, 280), a source of inflation fluid connected in fluid communication with one of the first and second inflatable portions (144, 150) of the seat belt (110, 110a, 110, 110aa) and connected in fluid communication with another of the first and second inflatable portions (150, 144) of the seat belt (110, 110a) through the member (114, 116, 116a, 280) and the one inflatable portion of the seat belt enabling inflation fluid to flow from the source of inflation fluid into the one inflatable portion of the seat belt and to flow from the one inflatable portion of the seat belt through the member (114, 116, 116a, 280) into the another inflatable portion of the seat belt, characterized in that the member (114, 116, 116a, 280) includes a locking portion (174, 224, 266, 268, 294) being pivotably mounted on the member (114, 116, 116a, 280) and around which the seat belt (110, 110a) extends when fastened and that applies a force against at least one of a central portion (176, 176a, 188, 256) and a longitudinally extending edge portion of the seat belt (110, 110a) while being ineffective to apply force to another of the central portion (176, 176a, 188, 256) and the longitudinally extending edge portion (180, 182). a seat belt (110, 110a), a member (114, 116, 116a, 280) having an opening (204, 204a, 290) through which the seat belt (110, 110a) extends, a first inflatable portion of the seat belt (110, 110a) extending in a first direction from the member (114, 116, 116a, 280), a second inflatable portion of the seat belt (110, 110a) extending in a second direction from the member (114, 116, 116a, 280), a source of inflation fluid connected in fluid communication with one of the first and second inflatable portions (144, 150) of the seat belt (110, 110a, 110, 110aa) and connected in fluid communication with another of the first and second inflatable portions (150, 144) of the seat belt (110, 110a) through the member (114, 116, 116a, 280) and the one inflatable portion of the seat belt enabling inflation fluid to flow from the source of inflation fluid into the one inflatable portion of the seat belt and to flow from the one inflatable portion of the seat belt through the member (114, 116, 116a, 280) into the another inflatable portion of the seat belt, characterized in that the member (114, 116, 116a, 280) includes a locking portion (174, 224, 266, 268, 294) being pivotably mounted on the member (114, 116, 116a, 280) and around which the seat belt (110, 110a) extends when fastened and that applies a force against at least one of a central portion (176, 176a, 188, 256) and a longitudinally extending edge portion of the seat belt (110, 110a) while being ineffective to apply force to another of the central portion (176, 176a, 188, 256) and the longitudinally extending edge portion (180, 182).