An EFP (Explosively Formed Penetrator) is a type of shaped charge that is often used against armored vehicles. It is a type of improvised explosive device (IED) that is highly dangerous and destructive. EFPs are unique from other bombs because they have a larger stand-off range, which makes them effective from a distance. They are comprised of a casing, high explosive filler, detonator, and a concave liner often made of copper. When detonated, the explosive charge deforms the liner into a slug-like projectile that can penetrate armor and cause significant post-penetration damage. EFPs have been adopted as warheads in a number of weapon systems, including air bombs, artillery rounds, and anti-tank missiles. They have also been used in improvised explosive devices against armored cars and coalition vehicles in Iraq and Afghanistan. EFPs were first developed during World War II as an effective way to take action from a stand-off distance.