I knew that some cars had tensioners, but had never heard of these before. "Seat belt inflator is also known as micro gas generator (MGG), which is a gas-generating device used for a mechanism in which the seatbelt is tightened in the case of a motor vehicle collision. When the seatbelt is tightened, the body of the occupant is affixed in the correct position and is aligned with the airbag. This enhances the effectiveness of the airbag, thereby ensuring the safety of the passenger."

Why am I not reassured when the mfgr says not to worry they'll explode on their own?