The M167 Vulcan Air Defense System (VADS) is a towed, short-range United States Army anti-aircraft gun designed to protect forward area combat elements and rear area critical assets. It was also used to protect U.S. Air Force warplane airfields and U.S. Army helicopter airfields. The heart of the M167 is the M168 Cannon, a variant of the M61 Vulcan 20×102 mm rapid-fire rotary cannon.

The M61 Vulcan is a hydraulically, electrically, or pneumatically driven, six-barrel, air-cooled, electrically fired Gatling-style rotary cannon which fires 20 mm × 102 mm rounds at an extremely high rate. The M61 and its derivatives have been the principal cannon armament of United States military fixed-wing aircraft for over sixty years.