The Pentagon announced last week that it will deliver 2,000 AT-4 anti-tank rockets to help Iraqi forces combat the Islamic State (IS), after the jihadist group seized Ramadi, the strategically important Anbar province capital. While not a sophisticated or expensive weapon, the AT-4 could prove a valuable addition to the arsenals of Iraqi ground forces struggling to hold off IS attacks.

The AT-4’s reliability made it a mainstay of the U.S. campaign against Sunni insurgents in Anbar from 2003 to 2011. Developed by Saab, the lightweight and shoulder-launched rocket uses a high-explosive projectile to penetrate buildings or armored vehicles. The single-shot AT-4 can pierce up to 350 millimeters of armor at 400 meters, but given that it is unguided, it is more effective at closer range.

While the AT-4 is ideal for urban combat scenarios like Ramadi, its real value could lie in stopping IS suicide car bombs – also known as suicide vehicle-borne improvised explosive devices (S-VBIEDs). According to the State Department, IS used as many as 30 S-VBIEDs in its assault on Ramadi last weekend, including 10 that equaled the magnitude of the 1995 Oklahoma City bombing.

For years, S-VBIEDs have been a common weapon for IS, its predecessor al-Qaeda in Iraq, and other regional jihadist groups. Recently, the militants have made them more deadly and difficult to stop as they are increasingly “up-armoring” them. IS has used bulldozers, tanks, armored personnel carriers, and trucks with improvised armor welded to their exteriors to protect against small-arms fire.

S-VBIEDs are often deployed at the start of an IS attack to break a hole in their opponent’s defenses that is then penetrated by swarms of fighters. That is where the AT-4 comes in: one or a few Iraqi soldiers armed with AT-4s could theoretically take out an S-VBIED at a safe distance to disrupt an entire IS assault. In some cases, particularly urban environments, an unguided AT-4 may be more effective than a guided anti-tank system, given the limited time to identify an approaching vehicle, aim, and fire. While Iraqi forces are already armed with similar weapons like rocket-propelled grenades, the AT-4 is more accurate, and most variants allow it to be fired from confined spaces like buildings and bunkers.

The AT-4 may not be as spectacular as advanced fighter jets armed with precision-guided bombs or as intimidating a battalion of Abrams tanks, but for the Iraqi soldiers manning checkpoints in Anbar, the AT-4 could make the difference in holding off an onslaught by the Islamic State.

Patrick Megahan is a research analyst at Foundation for Defense of Democracies focusing on military affairs. He manages the website militaryedge.org.