The M18A1 Claymore is the world's first factory-made directional fragmentation mine. The M18A1 Claymore anti-personnel mine was developed by designer Norman McLeod in the early 1950s in the United States. After general testing, this mine was adopted by the US Army. The M18A1 Claymore mine was widely used during the Vietnam War to protect strong points and posts of American units. The mines were used to line the approaches to the strong point and detonate them when the enemy threatened to approach.
The M18A1 mine body is a curved rectangle of olive-gray color, molded from fiberglass-reinforced plastic. The front surface is covered with steel balls arranged in a plastic matrix. The rear part of the body behind the matrix contains the C4 explosive. The fragmentation surface is convex horizontally, which allows the fragments to be directed within a 60-degree arc, and concave vertically to limit the spread of fragments in the vertical direction. Built-in sights and two pairs of folding scissor legs allow the mine to be installed in a pointed position. Two sockets for fuses are located in the upper part of the mine. Due to this, the mine can be activated from two different positions. The sockets are sealed with a blind end of the packaging safety plug/ignition coupling. When the mine is put into combat position, the coupling is installed at the other end. The slotted end is then used to hold the detonator cap.