The Claymore mine is a directional anti-personnel mine developed for the United States Armed Forces. Its inventor, Norman MacLeod, named the mine after a large medieval Scottish sword. Unlike a conventional land mine, the Claymore is command-detonated and directional, meaning it is fired by remote-control and shoots a wide pattern of metal balls into the kill zone. The Claymore can also be victim-activated by booby-trapping it with a tripwire firing system for use in area denial operations. The Claymore fires steel balls out to about within a 60° arc in front of the device. It is used primarily in ambushes and as an anti-infiltration device against enemy infantry. It is also used against unarmored vehicles. Many countries have developed and used mines like the Claymore. Examples include former Soviet Union models MON-50, MON-90, MON-100, and MON-200, as well as MRUD (Serbia), MAPED F1 (France), and Mini MS-803 (South Africa). Description The M18A1 Claymore mine has a horizontally convex gray-green plastic case (inert training versions are light blue or green with a light blue band). The shape was developed through experimentation to deliver the optimum distribution of fragments at range. The case has the words "FRONT TOWARD ENEMY" embossed on the front of the mine. A simple open sight on the top surface allows for aiming the mine. Two pairs of scissor legs attached to the bottom support the mine and allow it to be aimed vertically. On both sides of the sight are fuse wells set at 45 degrees. Internally the mine contains a layer of C-4 explosive behind a matrix of about seven hundred steel balls set into an epoxy resin. When the M18A1 is detonated, the explosion drives the matrix forward, out of the mine at a velocity of , at the same time breaking it into individual fragments. The steel balls are projected in a 60° fan-shaped pattern that is high and wide at a range of . The force of the explosion deforms the relatively soft steel balls into a shape similar to a .22 rimfire projectile. These fragments are moderately effective up to a range of , with a hit probability of around 10% on a prone man-sized target. The fragments can travel up to . The optimum effective range is , at which the optimal balance is achieved between lethality and area coverage, with a hit probability of 30% on a man-sized target. The