US Bomb, Guided, GBU-27/B
These are air-to-surface hard target penetrator guided bombs with a low level laser guidance system. Target illumination is achieved by a laser illumination device which may be ground mounted or carried in a target spotting aircraft. The GBUs are designed to penetrate subsurface multilayered hardened underground target structures when a high degree of accuracy is required. The GBU-27/B consists of a WGU-25/B, WGU-25A/B, or a WGU-39/B guidance control unit and a BSU-88/B airfoil group attached to a 2,000 pound (907 kilogram) BLU-109/B penetrator bomb.
Collaborative Ordnance Data Repository