The U.S. Department of Defense is buying 42 TigerShark UAVs for $760,000 each (including ground control equipment). These UAVs are equipped with the Cooperhead II Synthetic Aperture Radar, which can spot the wires used by the enemy to detonate roadside bombs. This has boosted the ability of American troops to spot roadside bombs in Afghanistan and greatly reduced the effectiveness of these weapons. The Tigershark is a 150 kg (263 pound) UAV that can carry 52 kg (115 pounds) for up to three hours, at an altitude as high as 4,500 meters (14,800 feet). Thus the Tigershark can fly above the range of ground fire and check roads for wire detonation bombs. U.S. forces have long carried jammers that make cell phones and other wireless devices useless for setting off these bombs.