The BLU-109/B is a hardened bunker buster penetration bomb used by the United States Air Force. As with other "bunker busters", it is intended to penetrate concrete shelters and other hardened structures before exploding. In addition to the US, it is part of the armament of the air forces of Australia, Belgium, Canada, Denmark, France, Germany, Greece, Italy, Israel, Netherlands, Norway, Pakistan, Saudi Arabia, United Kingdom, and United Arab Emirates.