Another product of the Advanced Bomb Family studies, the JDAM system consists of bolt-on subassemblies that can be added to standard Mk. 84, BLU-109B, and Mk.83 bombs to increase their accuracy. The tail assembly consists of the GPS and INS guidance units, as well as the control surfaces, and it is this assembly that guides the weapon to its target after release. The nose unit is simply a set of stabilizing fins and plays no role in weapon guidance. Because of their size, the F-22 must carry the GBU-31A and GBU-31A/B externally, but the GBU-32 can be carried within the main weapons bay.%n