Kontakt-5 is a type of third-generation explosive reactive armour originating in the Soviet Union

Soviet Union

The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

. It is the first type of ERA which is effectively able to defeat modern armour-piercing fin-stabilized discarding sabot (APFSDS) rounds.

Introduced on the T-80U tank in 1985, Kontakt-5 is made up of "bricks" of explosive sandwiched between two metal plates. The plates are arranged in such a way as to move sideways rapidly when the explosive detonates. This will force an incoming kinetic energy penetrator

Kinetic energy penetrator

A kinetic energy penetrator is a type of ammunition which, like a bullet, does not contain explosives and uses kinetic energy to penetrate the target....

 or shaped charge jet to cut through more armour than the thickness of the plating itself, since "new" plating is constantly fed into the penetrating body. A kinetic energy penetrator will also be subjected to powerful sideways forces, which might be large enough to cut the rod into two or more pieces. This will significantly reduce the penetrating capabilities of the penetrator, since the penetrating force will be dissipated over a larger volume of armour.

The effectiveness of Kontakt-5 ERA was confirmed by tests run by the German Bundeswehr

Bundeswehr

The Bundeswehr consists of the unified armed forces of Germany and their civil administration and procurement authorities...

 and the US Army

United States Army

The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...

. The Germans tested the K-5, mounted on older T-72 tanks, and in the US, Jane's IDR's

Jane's International Defence Review

Jane's International Defence Review is a monthly magazine reporting on military news and technology.The IDR is one of a number of military-related publications named after Fred T. Jane, an Englishman who first published Jane's All the World's Fighting Ships in 1898. It is a unit of Jane's...

 Pentagon

The Pentagon

The Pentagon is the headquarters of the United States Department of Defense, located in Arlington County, Virginia. As a symbol of the U.S. military, "the Pentagon" is often used metonymically to refer to the Department of Defense rather than the building itself.Designed by the American architect...

 correspondent Leland Ness confirmed that "when fitted to T-72 tanks, the 'heavy' ERA made them immune to the depleted uranium

Depleted uranium

Depleted uranium is uranium with a lower content of the fissile isotope U-235 than natural uranium . Uses of DU take advantage of its very high density of 19.1 g/cm3...

 penetrators of M829 APFSDS, fired by the 120 mm guns of the US M1 Abrams tanks, which were among the most formidable tank gun projectiles at the time." This is of course, provided that the round strikes the ERA, which only covers 60% of the frontal aspect of the T-72 series tank mounted with it.

Newer KE penetrators like the US M829A2 and now M829A3, have been improved to defeat the armor design of Kontakt-5.
The M829A2 was the immediate response, developed in part to take on the new armor bricks. The M829A3 is a further improvement of this as well and designed to fight future armor protection methods.

As a response to the M829A3, the Russian army have designed Relikt, the most modern Russian ERA, which is claimed to be twice as effective as Kontakt-5 . It detonates on command before the round hits based on information from radar. It can be installed on T-72B and T-90 tanks and is being tested in the Leningrad Military District, although Relikt is not actually in service on any Russian tank.

Kontakt-5 armour is employed by Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

 and Ukraine

Ukraine

Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...

.

Ideas have been drawn up for a new type of ERA called Kaktus which has been developed, although it has yet to be deployed.