ROOF-MOUNTED OCCUPANT RESTRAINT SYSTEM

A restraint system for helping to protect an occupant () of a vehicle () includes a first inflator () for providing inflation fluid at a first fluid pressure and a second inflator () for providing inflation fluid at a second fluid pressure greater than the first fluid pressure. An airbag () includes a stored condition within a roof () and is inflatable to a deployed condition extending into a cabin () and aligned with a seat () for the occupant (). The airbag () includes a first portion () defining a first chamber () fluidly connected to the first inflator () and a second portion () defining a second chamber () fluidly connected to the second inflator () and fluidly isolated from the first chamber (). The first portion () moves relative to the second portion () in response to occupant () penetration into the airbag ().