Our battery free ACOG-style rifle scopes (Advanced Combat Optic Gunsight) are equipped with a RED fiber optic illuminated inverted V-reticule that automatically adjusts the brightness based on available light. Similar to most of Red Dot sights, they can be used with both eyes open, which helps to improve situational awareness. Traditional windage and elevation adjustment dials, modern range-finding and bullet drop correction crosshair and detachable 20mm Picatinny mount. Protective lens coating is green