The BLU-109/B is a hardened penetration bomb used by United States military aircraft. (BLU is an acronym for Bomb Live Unit.) It is intended to smash through concrete shelters and other hardened structures before exploding. The BLU-109/B has a steel casing about 1 inch (25.4 mm) thick, filled with 530 lb (240 kg) of Tritonal. It has a delayed-action fuse. The BLU-109 entered service in 1985. It is also used as the warhead of some marks of the GBU-15 electro-optically guided bomb, the GBU-27 Paveway III laser-guided bomb, and the AGM-130 rocket-boosted weapon. This weapon supposedly has the same penetration as the Small Diameter Bomb, although it is not likely to be retired anytime soon, due to the much larger blast capable from its warhead.
