The M1,M1A1 and M4 are circular steel cased U.S.

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 anti-tank blast mine

Anti-tank mine

An anti-tank mine, , is a type of land mine designed to damage or destroy vehicles including tanks and armored fighting vehicles....

s with a distinctive cross shaped pressure spider. The mine was used during the Second World War and a copy produced in Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

 was used during the Falklands War

Falklands War

The Falklands War , also called the Falklands Conflict or Falklands Crisis, was fought in 1982 between Argentina and the United Kingdom over the disputed Falkland Islands and South Georgia and the South Sandwich Islands...

. Another copy is produced in China

China

Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

. designated the No.4 mine. Variants of the mine have also been deployed in Chad

Chad

Chad , officially known as the Republic of Chad, is a landlocked country in Central Africa. It is bordered by Libya to the north, Sudan to the east, the Central African Republic to the south, Cameroon and Nigeria to the southwest, and Niger to the west...

 and Tunisia

Tunisia

Tunisia , officially the Tunisian RepublicThe long name of Tunisia in other languages used in the country is: , is the northernmost country in Africa. It is a Maghreb country and is bordered by Algeria to the west, Libya to the southeast, and the Mediterranean Sea to the north and east. Its area...

.

Downward pressure on the spider presses down on the head of the fuze

Fuze

Fuze Beverage, commercially referred to as just Fuze , is a manufacturer of teas and non-carbonated fruit drinks enriched with vitamins. Currently the brand consists of five vitamin-infused lines: Slenderize, Refresh, Tea, Defensify, and Vitalize...

, breaks a shear pin, and inverts a belleville spring, flipping the striker

Firing pin

A firing pin or striker is part of the firing mechanism used in a firearm or explosive device e.g. an M14 landmine or bomb fuze. Firing pins may take many forms, though the types used in landmines, bombs, grenade fuzes or other single-use devices generally have a sharpened point...

 downwards into a stab sensitive detonator

Detonator

A detonator is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the latter two being the most common....

, triggering the mine. The M4 version of the mine has two secondary fuze wells so that anti-handling device

Anti-handling device

An anti-handling device is an attachment to or integral part of a landmine or other munition e.g. some fuze types found in air-dropped bombs such as the M83, cluster bombs and sea mines. It is specifically designed to prevent tampering. When the protected device is disturbed it detonates, killing...

s can be fitted.

Variants

• M1 - the mine has two filler plugs on the top surface.
• M1A1 - the mine has a single filler plug on the top surface.
• M4 - as the M1A1 but with two secondary fuze wells, one on the side one in the bottom.

Specifications

• Weight: 4.9 kg
• Explosive content: 2.75 kg of TNT
• Height: 75 mm
• Diameter: 204 mm
• Operating pressure: 250 kg to 120 kg