Inflator

An inflator for use in a safety device within a motor vehicle, the inflator comprising a hybrid multi-stage gas generator;

• the gas generator including a chamber accommodating compressed gas, a first pyrotechnic unit incorporating a first pyrotechnic charge configured so that, on actuation of the first pyrotechnic charge, hot gas from the pyrotechnic charge is directed into the chamber containing said compressed gas;
• and a second pyrotechnic unit incorporating a second pyrotechnic charge configured so that on actuation of the second pyrotechnic charge, hot gas from the second pyrotechnic charge is directed into the chamber containing the compressed gas;
• at least one gas outlet aperture being located in a flow path from the chamber containing compressed gas to the exterior of the inflator, the gas outlet aperture having an initial cross-section to define an initial gas flow area, the at least one gas outlet aperture incorporating a deformable part configured to deform in response to a predetermined gas pressure within the chamber, thereby increasing the cross-section of the gas outlet aperture to increase the gas flow area of the gas outlet.