An anti-aircraft gun is a type of artillery designed to target and destroy enemy aircraft. These guns can fire shells at high speeds and are often mounted on vehicles or fixed positions. They are used in military operations to protect ground forces and strategic locations from aerial attacks. Typically, anti-aircraft guns are equipped with radar systems to track incoming aircraft and improve accuracy. They can vary in size and caliber, with some being small enough to be portable, while others are large and require a crew to operate. Examples include the Bofors 40 mm and the Oerlikon 20 mm guns.