The JDAM GPS guided smart bomb was developed quickly during the 1990s. By the time the U.S. began bombing Kosovo in 1999, America had nearly a thousand JDAMs, and within months most of them had been used. Inventories were built up during the 1990s, although thousands of JDAMS were used to police the Iraqi no-fly zones and for training. By 2000, production was about 8900 JDAM a year. The JDAM itself is not a bomb, but a guidance kit that is attached to a bomb. Costing about $25,000 each these days, JDAM consists of GPS electronics, microcomputers, electrically actuated fins to guide the bomb and batteries to power it all. But then inventories were nearly used up again when American warplanes attacked Afghanistan, with some 6,000 JDAM being used up in about a year. But production was upped again, now running at about 34,000 JDAM kits a year. By the Fall of 2002, the U.S. had about 20,000 JDAM kits and was trying to build the inventory to over 200,000. Theres a downside to large inventories, because new enemy countermeasures, or any improvements in the weapons, requires a lot of time and money to modify the JDAMS in inventory. But if you have to fight a major war, you need those JDAMS. Now, not later. This is a common problem with high tech weapons. The technology tends to keep moving, and you have to keep moving with it to maintain that technological edge.