The Oerlikon cannon is a type of autocannon originally developed in Switzerland during the 1920s. It is known for its high rate of fire and versatility, making it suitable for various military applications, including anti-aircraft and naval defense. The cannon typically fires 20mm or 25mm rounds and has been widely used by many countries around the world. Over the years, the Oerlikon cannon has undergone several modifications and improvements, leading to different models. Its effectiveness in combat has made it a popular choice for both ground and naval forces, and it has been featured in numerous conflicts throughout the 20th and 21st centuries.