President Trump is facing a critical decision on whether to use America’s B-2 bombers to drop the GBU-57 “bunker-busting” bombs on the Fordow nuclear facility, which is buried in the mountains of Iran.

Doing so may be the only way to truly prevent Iran from acquiring a nuclear bomb, but it would also greatly increase U.S. involvement in the conflict and risk bringing the nation into a war in the Middle East.

Israel has neither the GBU-57 bomb or the B-2 bombers to fly them. Their use is seen as critical for hitting the Fordow facility.

What is the GBU-57

While a “bunk-buster” bomb is a broad term to refer to bombs designed to penetrate deep below the surface before exploding, Trump is deciding whether to utilize the latest GBU-57 A/B Massive Ordnance Penetrator (MOP) bomb currently residing in the American arsenal.

The latest bomb delivers 10 times more explosive power than its predecessor, the BLU-109, according to the Air Force.

The warhead is a large, GPS-guided, penetrating weapon with the ability to attack deeply-buried and hardened bunkers and tunnels, according to the latest report from the director of Operational Test and Evaluation (DOTE), which is part of the Office of the Secretary of Defense. It is known to penetrate about 200 feet below the surface before exploding.

The MOP is critical to taking out highly fortified targets buried under literal mountains, like those found in Iran, Russia, China, and North Korea, according to The War Zone. The guided weapon can impact the surface above its target with a high degree of accuracy.

B-2 stealth bomber

The only way to deliver the bomb is through a US B-2 stealth bomber, which can hold 40,000 pounds.

However, the U.S. Air Force said it has successfully tested the B-2 loaded with two of the GBU-57 A/B bunker busters, which, in total, weigh about 60,000 pounds, or about 30,000 pounds each.

Each bomb is about  20.5 feet long, according to the Air Force.

The warhead’s case is made from a special high-performance steel alloy, according to another report from the DOTE. The bomb’s design allows for a large explosive payload while maintaining the integrity of the penetrator case during impact.

The MOP is the most powerful, deeply burrowing non-nuclear bunker buster in the world. is critical to taking out highly fortified targets buried under literal mountains, like those found in Iran, Russia, China, and North Korea. The weapon is guided and can impact the surface above its target with a high degree of accuracy.

Development of the bomb began in 2004. In 2009, Boeing became the prime contractor to complete MOP/Aircraft integration.

As of 2015, Boeing had delivered at least 20 of the bombs. While the exact size of the current MOP stockpile is not known, it’s understood to be relatively small.