The M109 is a self-propelled howitzer used by the military for indirect fire support. It is designed to provide artillery firepower while being mobile on the battlefield. The M109 can fire various types of ammunition, including high-explosive and guided projectiles, making it versatile for different combat situations. Originally developed in the 1960s, the M109 has undergone several upgrades and variants, improving its range, accuracy, and technology. It is widely used by the United States Army and many allied forces around the world, showcasing its effectiveness in modern warfare.