you should always keep bubble wrap in your car incase of emergencies, if you are ever buried in an avakanche or landslide and the air is srunning out u can pop it, there is no air in the airbags in a car, they are packed flat and an explosive charge pumps them up.
Leg end you can ignore my advice but you wait until you are buried under a ton of snow the day after tomorow, i know the first thought will be, should have listened to dotty's advice lol
Its done the same way they get water into those ice cube bags actually but on a bigger scale, I hate mushrooms Roberto unless they are dripping in garlic butter and breadcumbs