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 tail-fuze. 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 IIIlaser-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.