Trijicons ACOG Advanced Combat Optical Gunsight is a fixed power compact riflescope with an illuminated reticle pattern for use in bright to lowno light with legendary durability and reliability. Every feature of its design was chosen for a single purpose to provide increased hit potential in all lighting conditions. Fewer moving parts than a variable optic equals more durability and the forged 7075T6 aircraftaluminumalloy housing provides for a nearly indestructible sighting system. Multicoated lenses provide superior clarity and lightgathering capabilities with zero distortion. The ACOG is drynitrogenfilled to eliminate fogging and waterproof to 100 meters. It is shockresistant proven to withstand recoil from 22LR up to 50 BMG and easily passes U.S. military drop test requirements.The ACOG ECOS is the ultimate sight for both Close Quarter battle CQB situations and longer distance shooting where accuracy and pinpoint bullet placement are required. It also features external windage and elevation adjusters making it waterproof up to 11m without caps. It also has a FDE finish.This model includes Trijicons 3.25 MOA RMR type two LED red dot and has a Tritium dual illuminated red crosshair reticle.