Hispano-Suiza HS.404

The HS.404 is an autocannon originally designed by and produced by the Swiss arm of the Spanish–Swiss company Hispano-Suiza in the mid-1930s. Production was later moved to the French arm of Hispano-Suiza.

It was widely used as an aircraft, naval and land-based weapon by French, British, American and other military services, particularly during World War II. The cannon is also referred to as Birkigt type 404, after its designer Marc Birkigt and later versions based on British development are known as 20 mm Hispano.

Firing a 20 mm calibre projectile, it delivered a significant load of explosive from a relatively light weapon.