Trijicon ACOG, 3X24mm, Dual Illuminated Red Horseshoe/Dot 223/55 Grain, Includes Q-LOC Mount, Matte Finish, Black TA50-C-400348 There's a reason the Trijicon ACOG (Advanced Combat Optical Gunsight) is the official medium-distance engagement optic of the U.S. Marine Corps and U.S. Special Operations Forces. And why more than one million have been produced. Each one is specifically engineered to provide increased hit potential in all lighting conditions, while also providing legendary durability and reliability.