Artillery has quickly become the most important weapon in Ukraine’s war with Russia.

Ukrainian forces have begun to use newer Western artillery, like the M777 Howitzer, in the battlefield. But a different kind of weapon has had a bigger impact. The American-made High Mobility Artillery Rocket System, aka HIMARS, has been a major high-tech upgrade for Ukraine’s military.

“The introduction of the HIMARS rocket artillery to Ukraine has been significant,” said George Barros, a geospatial analyst at the Institute for the Study of War. “That has changed the battlefield quite a lot. And it really goes to show that Western aid to Ukraine is not just paper pushing or symbolic.”

Ukrainian forces claimed to have already used the HIMARS to take out ammunition dumps, command posts and other high-value targets. Providing this high-tech system could help Ukraine blunt Russian advances and change the direction of the conflict.

“What the United States needs to do is to have a strategy to bring this war to an early end,” said George Beebe, director of grand strategy at the Quincy Institute. “That means not only convincing the Russians that they can’t win on the battlefield but also showing them that should they make concessions at the negotiating table.”

Watch the video above to find out more about how the high-tech, American-made mobile-rocket artillery system known as HIMARS could help Ukrainian forces repel the Russian invasion, and why some fear the potent weapon could lead to further escalation of hostilities between Russia and the West.