TRIJICON ACOG RCO 4X32 RED CHEV M4The Trijicon ACOG RCO 4x32 Red Chevron M4 Riflescope is a combat proven optic designed specifically for the M4 and M4A1 weapon system with a 14. 5" barrel. This Advanced Combat Optical Gunsight (ACOG) features dual illumination technology, combining fiber optics and tritium for a constantly illuminated reticle without batteries. The 4x magnification and 32mm objective lens provide excellent target identification and hit probability up to 800 meters.