In the late 1960s, a Pennsylvania man named Alan Litman fretted that his wife wouldn’t be safe coming home late on the mean streets of Pittsburgh. So he did what any doting husband would do—he figured out a way to fill a portable, easily deployed spray can with tear gas. Then he started marketing the product to law enforcement. Today his invention is known as Mace, a brand now synonymous with private citizens packing a ton of heat.

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