The #77 punch-out tool or automatic center punch is a life saving tool when trapped in an automobile. It will shatter side windows of your car or truck even under water. The Punch-Out Tool is the preferred tool to free victims trapped in automobiles by paramedics, police and fire rescue. Just press the tool to the window surface with a single hand and the spring loaded tool delivers the punch without the need to strike with a hammer. - Stroke force is adjustable by turning the end cap. Carry this tool in your glove compartment or console for easy accessibility in case of emergency or the unexpected time you may be trapped in your vehicle. Ball bearing automatic center punch with unique ball bearing action.