The Joint Direct Attack Munition (JDAM), is the designation for a guidance kit, to upgrade unguided bombs, into precision guided munitions or "smart" bombs. These JDAMs are directed to their target by an inertial guidance system (INS), in combination with a Global Positioning System (GPS), but some variants are also laser guided. JDAMs are in use since the 1999 Kosovo War. They were used up to 10,000 times and are considered as one of the most important parts of the air-to-surface armament of the Western countries. The costs for a single upgrade kit for a Mk-80 series bomb, are about 30,000 US-Dollars.