An ACOG (Advanced Combat Optical Gunsight) is a series of magnified weapon scopes made by the American company Trijicon. Their scopes commonly offer a magnification of 4x, meaning anything viewed down the scope will be four times bigger than when viewed normally. Usually, ACOG scopes utilize luminescent materials such as Tritium or optical fibers to improve aiming and target acquisition. The ACOG series of weapon scopes is used by the US Armed Forces, as well as parts of other nations' armies such as the British Armed Forces.