Original Item: Only One Available. An opposing force (alternatively enemy force, abbreviated OPFOR) is a military unit tasked with representing an enemy, usually for training purposes in war game scenarios. The related concept of aggressor squadron is used by some air forces. The United States maintains the Fort Irwin National Training Center with the 11th Armored Cavalry Regiment serving in the OPFOR role. Fort Polk's Joint Readiness Training Center (JRTC)is another major training site typically reserved for light infantry units, and the OPFOR are the 1st of the 509th Airborne Infantry Regiment. The Army's Joint Maneuver Readiness Center (JMRC, at Hohenfels, Bavaria, Germany) has the 1st of the 4th Infantry Regiment as their OPFOR. Other major units include the First United States Army which consists of 16 training brigades that often also serve as OPFOR.

At a basic level, a unit might serve as an opposing force for a single scenario, differing from its 'opponents' only in the objectives it is given. However, major armies commonly maintain specialized groups trained to accurately replicate real-life enemies, to provide a more realistic experience for their training opponents. (To avoid the diplomatic ramifications of naming a real nation as a likely enemy, training scenarios often use fictionalized versions with different names but similar military characteristics to the expected real-world foes.)

Some dedicated opposing forces may fight using the likely enemy's doctrine, weapons, and equipment. They may wear uniforms which resemble the likely enemy's, or one dissimilar to "friendly forces". Their vehicles may either be those operated by the likely enemy's, or may be modified to look like those. All these measures help to enhance training realism and provide useful lessons on how to fight this particular enemy.

This OPFOR M1 helmet liner is a great example of the type of uniforms worn. The liner is a true WWII constructed high pressure helmet liner by CAPAC. It is stamped with the Capac Manufacturing Company logo with a frontal eyelet. Manufactured in Capac, Michigan this high pressure manufactured M-1 helmet liner is identified by an embossed cross with the words Capac in the crown. Capac Manufacturing Company started M-1 helmet liner delivery to the US Army in September 1942. They produced approximately between 2,000,000 - 4,000,000 M-1 helmet liners and discontinued production around August 17 1945 when the war ended.

The liner is painted all black and was probably paired with a set of an all black uniform. The liner has a black wooden comb on top, to easily distinguish the user as an unfriendly element, giving them a different silhouette than the other forces apart from the war games. The wooden comb is attached by a single wood screw and is free of major damage.

This is a wonderful example of the seldom seen OPFOR helmet. Most of these modified helmets were discarded after use, so finding one in as good of a condition as this one is a rarity! Comes ready for display.

Military Exercise
A military exercise or war game is the employment of military resources in training for military operations, either exploring the effects of warfare or testing strategies without actual combat. This also serves the purpose of ensuring the combat readiness of garrisoned or deployable forces prior to deployment from a home base.

War games involving two or more countries allows for better coordination between militaries, observation of enemy's tactics, and is a visible show of strength for the participating countries. According to a 2021 study, joint military exercises within well-defined alliances usually deter adversaries without producing a moral hazard because of the narrow scope of the alliance, while joint military exercises outside of an alliance (which are extremely rare) usually lead to conflict escalation.

Exercises in the 20th and 21st centuries have often been identified by a unique codename, such as Cobra Gold, in the same manner as military contingency operations and combat operations like Operation Phantom Fury.

Military exercises are sometimes used as cover for build up to an actual invasion such as in the cases of the Warsaw Pact invasion of Czechoslovakia and the 2022 Russian invasion of Ukraine, or it can provoke opponents at peace to perceive it as such in the case of Able Archer 83.