[citation needed] Unlike a conventional land mine, the Claymore may be command-detonated (fired by remote-control), and is directional, shooting a wide pattern of metal balls into a kill zone.

Examples include models MON-50, MON-90, MON-100, and MON-200 introduced by the Soviet Union and used by its successor Russia,[3] as well as MRUD (Serbia), MAPED F1 (France), and Mini MS-803 (South Africa).

Internally the mine contains a layer of C-4 explosive behind a matrix of about seven hundred 1⁄8-inch-diameter (3.2 mm) 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 1,200 m/s (3,937 ft/s),[1] at the same time breaking it into individual fragments.

The optimum effective range is 50 m (55 yd), at which the optimal balance is achieved between lethality and area coverage, with a hit probability of 30% on a man-sized target.

When mines are employed in the controlled role, they are treated as individual weapons and are reported in the unit fire plan.

[1] Following the massed Chinese attacks during the Korean War, Canada and the United States began to develop projects to counter them.

Canada fielded a weapon called the "Phoenix" landmine, which used the Misnay–Schardin effect to project a spray of 0.25-inch (6.4 mm) steel cubes towards the enemy.

[1] Around 1952 Norman MacLeod, at his company the Calord Corporation, began working on a small directional mine for use by infantry.

Through Picatinny, the United States Army accepted the weapon into service as the M18 Claymore and approximately 10,000 were produced.

The mine was planted in the ground, using its three sharp legs, and aimed in the direction of enemy approach; at that point, it was fitted with an electrical blasting cap.

The mine was barely more than a prototype and was not considered a "reliable casualty producer"; like the Phoenix it had an effective range of only 90 feet (27 m).

[7] The patent was later the subject of a civil court case between MacLeod, the Army, and Aerojet, which further developed the Claymore design.

MacLeod's case collapsed when photographs of the German Trenchmine prototype were produced as evidence of prior art.

[1] Technical challenges to overcome included developing a case to contain the corrosive C-3 explosive that would be durable enough to withstand months of field handling in wide temperature ranges.

Bill Kincheloe came up with the idea of using a "Tiny Tim" toggle generator, of the type used with a number of Navy rockets.

After locating a suitably low-cost device, the engineers found that fumes from either the C-3 explosive or the cement used to glue the sight to the top of the mine corroded the plastic mirrors, rendering them unusable.

Testing concluded that the mine was effective out to approximately 110 yards (100 m), being capable of hitting 10% of the attacking force.

The light blue or black plastic M33 Inert Anti-Personnel Mine is the training and practice version of the M18A1 Claymore.

It is packed in a Claymore bag with inert M10 simulated detonator cap wire, an M57 "clacker" firing control, and an M40 circuit test kit.

In early 2015, the U.S. Army began testing a smaller version of the Claymore called the Mini-Multi-Purpose Infantry Munition (M-MPIMS).

The M-MPIMS is designed to be more controllable than the Claymore with less collateral damage, using an insensitive munitions explosive that is poured rather than packed for more uniform distribution results in more consistent blast pattern.

[9] PADMINE is an anti-personnel directional fragmentation mine produced by the United Kingdom, similar to the Claymore in cosmetic design with two swivelling legs, inserted into soft-ground.

Its lethality out to 50 meters arrives in the form of 650 steel balls and it is activated by remote control or trip wire.