Trijicon's ACOG (Advanced Combat Optical Gunsight) is a fixed power, compact riflescope with an illuminated reticle pattern for use in bright to low/no 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 7075-T6 aircraft-aluminum-alloy housing provides for a nearly indestructible sighting system. Multi-coated lenses provide superior clarity and light-gathering capabilities with zero distortion. The ACOG is dry-nitrogen-filled to eliminate fogging and waterproof to 100 meters. It is shock-resistant, 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 Trijicon's 3.25 MOA RMR type two LED red dot and has a Tritium dual illuminated red crosshair reticle.