The U.S. Army has successfully tested BAT anti-tank missiles launched from Hunter UAVs. The BAT is three feet long, 5.5 inches in diameter and, in this "Viper Strike" configuration, about 40 pounds. Normally, it uses acoustic and heat seeking to find armored vehicles, which it destroys from the top with a five pound warhead. But the "Viper Strike" version uses laser guidance, for attacks on urban targets where you want to avoid injuring nearby civilians. The BAT is unpowered, which is why it is so light. Normally it is ejected from a larger missile within a kilometer or two from its target. The battery powered BAT pops out four wings and moves these to glide and maneuver itself to a target below. Dropping a "Viper Strike" from a UAV at a target below has worked in tests, destroying individual vehicles or large weapons (missile launchers or artillery.)