The Res-Q-Me car escape tool is the perfect device for escaping a vehicle in an emergency and is small enough to fit on your key chain. It has an integrated seatbelt cutter and window punch, both with safety covers. Made in California from strong ABS plastic and stainless steel, they are available in a variety of colors.
To use: simply push the black circle against a corner of the window and the spring loaded striker breaks the window. So easy to use a child can do it! (Which isn't funny, it's actually terrifying, but true.)